Weather fronts act as the forces that push high and low pressure systems around all over the country and all over the globe. These high and low pressure systems are called air masses, and they can either be warm and dry and nice or cold and snowy and miserable. They are called cold fronts and warm fronts and bring with themselves unique traits--and densities. The density of a cold front is greater than that of a warm front because of the expansion of gases in warm fronts that cause them to rise above cold fronts. Sometimes, these two air masses meet and clouds form, dropping precipitation. We often hear about tornadoes forming in areas where cold fronts and warm fronts collide. Cold fronts tend to spit out precipitation in violent bursts whereas a warm front might only drop a slight drizzle over a region. Almost always, the location of an air mass is also the location of cloud cover and high/low pressure.
Problems:
4.) A cold front is approaching your town, expected to arrive tomorrow. What kind of weather can you expect? The cold front will most likely cause a drop in temperature, thicker clouds, and the potential for either a lot of drenching rain or a lot of snow. I'd best set out my beanie!
5.) A warm front is approaching your town, expected to arrive tomorrow. What kind of weather can you expect? I might prepare for an increase in temperature, perhaps slight rain, and possible cloud cover. If clouds do form, they might be light and airy rather than thick and clumpy and overcast.
Sunday, September 30, 2012
Unit 3, Lesson 6
This was quite a gassy lesson!
...No...? Oh, alright. Moving on...
We discussed Charles' Law. Charles' Law simply states that the volume and temperature of a gas sample are proportional to each other through the use of a constant, which we represent as a lowercase k. The equation for finding the constant, k, the volume, or the temperature of a sample is as follows:
...No...? Oh, alright. Moving on...
We discussed Charles' Law. Charles' Law simply states that the volume and temperature of a gas sample are proportional to each other through the use of a constant, which we represent as a lowercase k. The equation for finding the constant, k, the volume, or the temperature of a sample is as follows:
V= kT
k = V/T
T = V/k
The proportionality constant varies depending on the size of the sample of gas that you have.
Problems:
1.) Explain how to find the proportionality constant for a sample of gas. If you know that you can find volume by multiplying k and the temperature of your sample, you can scramble the equation (which I have so graciously done above) and divide volume by temperature to get your constant.
4.) A sample of gas in a cylinder has a volume of 980 mL at a temperature of 27 degrees Celsius. If you allow the piston to move while you heat the gas to 325 K, what will the volume of the gas be at 130 degrees C?
27 degrees C = 300 K. 130 degrees C = 403
980/300 = 3.26
403(3.26) = 123.6 or about 124 mL
Unit 3, Lesson 5
Here, we were introduced to the third and final temperature scale (remember how I mentioned there being three in my lesson 4 post?). It's called the Kelvin scale. It does not require the use of a degree mark, only a capital K. Associated with Kelvin is the term 'absolute zero', which is a temperature we haven't been able to reach, but have gotten quite close to. To find a Kelvin temperature, you can use these formulas:
K = C + 273
C = K - 273
As a side-note, keep in mind that molecules/particles in a sample of gas are always moving. An object in motion will stay in motion unless an outside force interferes with it. Particles travel in straight lines until they bump into each other or into a wall.
Problems:
5.) Which unit is the smallest: one Celsius degree, one Kelvin, or one Fahrenheit? You find a Kelvin degree by adding 273 to a Celsius degree, which makes Kelvins the biggest units of temperature and Celsius the next step down. Because a Celsius degree can encompass many Fahrenheit degrees, Fahrenheit is the smallest unit of temperature measurement.
9.) Convert these temperatures to the Kelvin scale.
A.) 95 degrees F (hot day)
95 = 1.8(C) + 32 K = C + 273
-32 -32 K = 35 + 273
------------------- K = 308
63 = 1.8(C)
-------------------
C = 35
B.) 350 degrees F (oven temperature)
350 = 1.8(C) +32 K = C _273
-32 -32 K = 176.6666666666667 + 273
----------------------- K = about 450
318 = 1.8(C)
-----------------------
C = 176.6666666666667 (didn't round yet!)
C.) 5 degrees F (freezer temperature)
5 = 1.8(C) + 32 K = C +273
-32 -32 K = -15 + 273
------------------ K = 258
-27 = 1.8(C)
------------------
C = -15
5.) Which unit is the smallest: one Celsius degree, one Kelvin, or one Fahrenheit? You find a Kelvin degree by adding 273 to a Celsius degree, which makes Kelvins the biggest units of temperature and Celsius the next step down. Because a Celsius degree can encompass many Fahrenheit degrees, Fahrenheit is the smallest unit of temperature measurement.
9.) Convert these temperatures to the Kelvin scale.
A.) 95 degrees F (hot day)
95 = 1.8(C) + 32 K = C + 273
-32 -32 K = 35 + 273
------------------- K = 308
63 = 1.8(C)
-------------------
C = 35
B.) 350 degrees F (oven temperature)
350 = 1.8(C) +32 K = C _273
-32 -32 K = 176.6666666666667 + 273
----------------------- K = about 450
318 = 1.8(C)
-----------------------
C = 176.6666666666667 (didn't round yet!)
C.) 5 degrees F (freezer temperature)
5 = 1.8(C) + 32 K = C +273
-32 -32 K = -15 + 273
------------------ K = 258
-27 = 1.8(C)
------------------
C = -15
Saturday, September 29, 2012
Unit 3, Lesson 4
Though Chemistry includes three temperature scales, this lesson only touched on two: Celsius and Fahrenheit. Substances become hot or cold depending on how fast their molecules are moving. Keep in mind as a side note that fast-moving particles usually result in gas that expands to take up more space. Hence, "excited" particles make for hotter temperatures. Alternatively, however, some particles move sluggishly and tend to cause gases to compact, or contract, which means that they get smaller. Similar to the way that a person curls into a ball with a blanket when they're cold, the compacted molecules make for cooler temperatures. At that point, we get ice.
Hotness and coolness are measured in Fahrenheit and Celsius through the use of the term degrees. The two scales are drastically different from one another. One increment in Celsius accounts for an enormous jump in degrees Fahrenheit, which means that you could easily screw up a measurement if you don't pay attention!
A formula for converting Celsius from Fahrenheit is as follows:
Hotness and coolness are measured in Fahrenheit and Celsius through the use of the term degrees. The two scales are drastically different from one another. One increment in Celsius accounts for an enormous jump in degrees Fahrenheit, which means that you could easily screw up a measurement if you don't pay attention!
A formula for converting Celsius from Fahrenheit is as follows:
F = 1.8 (C) + 32
OR
F = 9/5 (C) + 32
Problems:
1.) Explain how the height of a liquid can be used to measure temperature. As the temperature of a substance increases, the particles in that substance begin to move faster and faster, growing more "excited" if you will, and that causes the liquid, gas, whatever you might have, to expand. If in a container, the expanding substance will grow and its height will increase. Liquid inside a thermometer rises to a certain tic mark on the side of a glass tube to tell the temperature of something.
5.) Convert -40 degrees C to F. Show your work.
F = 1.8 (-40) +32
F = -38.2 + 32
F = -6.2
F = -6 degrees
1.) Explain how the height of a liquid can be used to measure temperature. As the temperature of a substance increases, the particles in that substance begin to move faster and faster, growing more "excited" if you will, and that causes the liquid, gas, whatever you might have, to expand. If in a container, the expanding substance will grow and its height will increase. Liquid inside a thermometer rises to a certain tic mark on the side of a glass tube to tell the temperature of something.
5.) Convert -40 degrees C to F. Show your work.
F = 1.8 (-40) +32
F = -38.2 + 32
F = -6.2
F = -6 degrees
Unit 3, Lessons 2 and 3
Lesson two explained to us the proportionality between volume and height for different containers. In a container with a base shaped similar to the top, with parallel sides, volume and height are exactly proportional. If you change the size of your container, your height might change, but your volume won't. Lesson 3 gave us a more in-depth look at this. We learned the densities of rain and snow, which are as follows:
Rain - D = 1 g/mL
Snow - D = 0.5 g/mL
This occurs because snow is lighter, fluffier if you will, than liquid rain when you put it in a container. If you were to watch snow melt (wouldn't that be exciting) you'd have the same density as rain.
Certain formulas come in handy when you're trying to figure out mass, density, and volume. They are as follows:
Volume: V= M/D
Density: D= M/V
Mass: M= V x D
Lesson 2 Problems:
2.) Explain in your own words why meteorologists prefer to measure rain in inches or centimeters, not in milliliters or cubic centimeters. Meteorologists prefer to measure rain in inches or centimeters as opposed to milliliters or cubic centimeters because the last two units typically refer to volume, which can fluctuate depending on what type of container liquid is being kept in. Height, on the other hand, which is measure in inches or centimeters, does not depend on the diameter of a rain gauge or other container.
5.) If a large washtub, a dog's water dish, and a graduated cylinder were left outside during a rainstorm, would the three containers have the same volume of water in them after the storm? Explain why or why not. The three containers would not have the same volume of water in them after the rainstorm. While they all probably have circular bases and parallel walls, the base of the washtub is most certainly larger in diameter than that of the graduated cylinder, and the water dish falls between those two. Since volume is related to diameter and fluctuates based on the amount of space needed to be filled, the three containers might not collect the same volume. (I'm prepared for this answer to be terribly wrong.)
5.) If a large washtub, a dog's water dish, and a graduated cylinder were left outside during a rainstorm, would the three containers have the same volume of water in them after the storm? Explain why or why not. The three containers would not have the same volume of water in them after the rainstorm. While they all probably have circular bases and parallel walls, the base of the washtub is most certainly larger in diameter than that of the graduated cylinder, and the water dish falls between those two. Since volume is related to diameter and fluctuates based on the amount of space needed to be filled, the three containers might not collect the same volume. (I'm prepared for this answer to be terribly wrong.)
Lesson 3 Problems:
3.) How are snow and ice different? While they're both made of water, snow is often times fluffier and lighter than ice. Because snow crystals are like ice that's been shredded up, they have a lower density than solid ice, which you can hold in chunks in your hand. You can feel ice's weight. Density changes with physical changes, which means that the densities of liquid water, ice, and snow are all different.
8.) Suppose you have a box that is full and contains 500 grams of a substance.
A.) What is the volume of the box if the substance inside is corn oil? (The density of corn oil is 0.92 g/mL)
3.) How are snow and ice different? While they're both made of water, snow is often times fluffier and lighter than ice. Because snow crystals are like ice that's been shredded up, they have a lower density than solid ice, which you can hold in chunks in your hand. You can feel ice's weight. Density changes with physical changes, which means that the densities of liquid water, ice, and snow are all different.
8.) Suppose you have a box that is full and contains 500 grams of a substance.
A.) What is the volume of the box if the substance inside is corn oil? (The density of corn oil is 0.92 g/mL)
V = M/D
V = 500/0.92
V = 543. 47
The volume of your box is most likely about 543 mL.
Unit 3, Lesson 1
If you're ready for this new unit, put your hands up!
Anyone else excited...? No...?
Ah, well, I tried.
Today we discussed lesson 1 of unit 3. The lesson talked about weather maps and how meteorologists use them to predict what conditions a given region will experience. There are maps that chart out cloud cover, precipitation, temperatures for different areas, and where pockets of high and low pressure are found. In addition to these helpful tools, there are also maps that display fronts and the jetstream. The jetstream, a constant current of wind (similar to the current you might've heard about running through the ocean) that divides the country in half, travels at about 57 mph, 4 miles above the ground, in a west-to-east motion. It gives flights head-winds and tail-winds, which mean that if you're flying, you might arrive at your destination earlier or a tad late. Fronts are "waves" if you will that push temperature, cloud cover, and precipitation into areas north or south of the jetstream. The type of precipitation that falls varies in areas of high or low pressure, which means that the southern United States will generally be more humid, overcast, and wet than the north and midwest regions.
Problems:
1.) What substances are necessary in order for a planet to have weather? Substances that make up the atmosphere, like gases and water vapor, must be present in order for a planet to have weather. An atmosphere creates an apparatus around the planet in which weather phenomena can occur.
3.) What is a physical change? A physical change is any form that a substance takes after conditions around that substance change. An example of a physical change would be ice melting into liquid water on a hot day or when sitting at room temperature.
Anyone else excited...? No...?
Ah, well, I tried.
Today we discussed lesson 1 of unit 3. The lesson talked about weather maps and how meteorologists use them to predict what conditions a given region will experience. There are maps that chart out cloud cover, precipitation, temperatures for different areas, and where pockets of high and low pressure are found. In addition to these helpful tools, there are also maps that display fronts and the jetstream. The jetstream, a constant current of wind (similar to the current you might've heard about running through the ocean) that divides the country in half, travels at about 57 mph, 4 miles above the ground, in a west-to-east motion. It gives flights head-winds and tail-winds, which mean that if you're flying, you might arrive at your destination earlier or a tad late. Fronts are "waves" if you will that push temperature, cloud cover, and precipitation into areas north or south of the jetstream. The type of precipitation that falls varies in areas of high or low pressure, which means that the southern United States will generally be more humid, overcast, and wet than the north and midwest regions.
Problems:
1.) What substances are necessary in order for a planet to have weather? Substances that make up the atmosphere, like gases and water vapor, must be present in order for a planet to have weather. An atmosphere creates an apparatus around the planet in which weather phenomena can occur.
3.) What is a physical change? A physical change is any form that a substance takes after conditions around that substance change. An example of a physical change would be ice melting into liquid water on a hot day or when sitting at room temperature.
Thursday, September 20, 2012
Unit 1 review
In this unit, we learned about almost everything under the sun that relates to atoms, atomic bonding, and reactions. We began by learning about significant figures, which are a sidenote of sorts but still important when doing math in Chemistry. From there we touched on the periodic table, discussing its groups and their properties and the patterns that cause the table to look how it does today. By learning the groups, we acquired knowledge of what elements are quick to bond and which are not, and how violently some react with other substances (such as the elements in Group 1A in water). For a brief while we discussed what atoms are made up of, constantly reminding ourselves that atomic numbers are equal to the numbers of protons. Our plethora of lessons helped us learn about bonds, what keeps atoms together, and how things like electrons are found (their arrangement) in atoms.
Problems:
4.) Describe nuclear fission and nuclear fusion. While nuclear fusion implies that two nuclei are joined together in a display of heat and energy to create a new, bigger nucleus and a new element, nuclear fission requires one nucleus to be split apart into two smaller nuclei. The two products are usually of the same element, but are different from the atom that was split apart. Fission also requires generous amounts of heat and energy to occur.
7.) What are cations and anions? They are the positively and negatively charged atoms in a compound. Typically, their charges are balanced to come out with something neutral. The cations are positive, while the anions are negative (remember that nifty trick I mentioned a few posts back? No? Oh well...)
11.) A substance does not dissolve in water and does not conduct electricity. What kind of bond keeps it together? It is most likely bonded with network covalence.
Problems:
4.) Describe nuclear fission and nuclear fusion. While nuclear fusion implies that two nuclei are joined together in a display of heat and energy to create a new, bigger nucleus and a new element, nuclear fission requires one nucleus to be split apart into two smaller nuclei. The two products are usually of the same element, but are different from the atom that was split apart. Fission also requires generous amounts of heat and energy to occur.
7.) What are cations and anions? They are the positively and negatively charged atoms in a compound. Typically, their charges are balanced to come out with something neutral. The cations are positive, while the anions are negative (remember that nifty trick I mentioned a few posts back? No? Oh well...)
11.) A substance does not dissolve in water and does not conduct electricity. What kind of bond keeps it together? It is most likely bonded with network covalence.
Lessons 25 and 26
Lesson 25:
This lesson summarized the four ways that atoms can bond together. They are as follows: metallic, ionic, molecular covalent, and network covalent. Elements fall into these categories based on their conductive and soluble properties. Other identifying factors include the elements themselves: are they nonmetals, metals, or both? Usually, metals conduct electricity while nonmetals do not, and if the two are stuck together and dissolved, the compound is soluble and sometimes still conductive.
Problems:
1.) What does insoluble mean? Insoluble simply means that a compound or substance cannot be dissolved in water or any other liquid.
3.) What generalization can you make about a substance that is soluble in water and can conduct electricity when dissolved? Explain your reasoning. This substance is most likely an ionic compound. If it conducts electricity when dissolved, that means it contains a metal, and typically ionic compounds can be dissolved because they have a nonmetal element in them.
Lesson 26:
Lesson 25 hinted vaguely at what 26 would be about; we learned exactly what the four categories that elements fall into are called. Metallic, ionic, molecular covalent, and network covalent are used to describe how the electrons in atoms keep compounds "glued" together. Metallic bonds usually describe single, metal elements. An example of this would be a solid gold ring. It conducts, but does not dissolve, and is made SOLELY of metal atoms. Ionic bonds describe metals and nonmetals bonded together. They dissolve, conduct, and conduct when dissolved. Molecular covalent compounds can sometimes dissolve, as some are liquids and some are gases, but they do not conduct electricity. Typically, we see molecular covalence in compounds made completely of nonmetals. Finally, network covalent compounds neither dissolve nor conduct electricity. The electrons in network covalent compounds are so tightly stuck together, almost in a lattice-like pattern, that the substances resulting from them are very hard to break apart. Diamond is a great example, being one of the hardest rocks on Earth.
Problems:
3.) Determine the type of bonding in each substance:
A.) zinc, Zn - Metallic bond, single element.
B.) propane, C3H8(l) - Molecular covalent, liquid nonmetal compound
C.) calcium carbonate, CaCO3(s) - Ionic bond, solid metal and nonmetal compound
7.) Suppose you have a mixture of sodium chloride, NaCl, and carbon, C. Explain how you can use water to separate the two substances. NaCl in itself is an ionic compound that is soluble in water. The sodium and chlorine completely break apart, allowing the sodium to conduct electricity through the water. The chlorine, being a nonmetal, doesn't do much, and if you added carbon to the compound, you'd have atoms of sodium, chlorine, and carbon floating around in water. To separate them would be quite easy.
This lesson summarized the four ways that atoms can bond together. They are as follows: metallic, ionic, molecular covalent, and network covalent. Elements fall into these categories based on their conductive and soluble properties. Other identifying factors include the elements themselves: are they nonmetals, metals, or both? Usually, metals conduct electricity while nonmetals do not, and if the two are stuck together and dissolved, the compound is soluble and sometimes still conductive.
Problems:
1.) What does insoluble mean? Insoluble simply means that a compound or substance cannot be dissolved in water or any other liquid.
3.) What generalization can you make about a substance that is soluble in water and can conduct electricity when dissolved? Explain your reasoning. This substance is most likely an ionic compound. If it conducts electricity when dissolved, that means it contains a metal, and typically ionic compounds can be dissolved because they have a nonmetal element in them.
Lesson 26:
Lesson 25 hinted vaguely at what 26 would be about; we learned exactly what the four categories that elements fall into are called. Metallic, ionic, molecular covalent, and network covalent are used to describe how the electrons in atoms keep compounds "glued" together. Metallic bonds usually describe single, metal elements. An example of this would be a solid gold ring. It conducts, but does not dissolve, and is made SOLELY of metal atoms. Ionic bonds describe metals and nonmetals bonded together. They dissolve, conduct, and conduct when dissolved. Molecular covalent compounds can sometimes dissolve, as some are liquids and some are gases, but they do not conduct electricity. Typically, we see molecular covalence in compounds made completely of nonmetals. Finally, network covalent compounds neither dissolve nor conduct electricity. The electrons in network covalent compounds are so tightly stuck together, almost in a lattice-like pattern, that the substances resulting from them are very hard to break apart. Diamond is a great example, being one of the hardest rocks on Earth.
Problems:
3.) Determine the type of bonding in each substance:
A.) zinc, Zn - Metallic bond, single element.
B.) propane, C3H8(l) - Molecular covalent, liquid nonmetal compound
C.) calcium carbonate, CaCO3(s) - Ionic bond, solid metal and nonmetal compound
7.) Suppose you have a mixture of sodium chloride, NaCl, and carbon, C. Explain how you can use water to separate the two substances. NaCl in itself is an ionic compound that is soluble in water. The sodium and chlorine completely break apart, allowing the sodium to conduct electricity through the water. The chlorine, being a nonmetal, doesn't do much, and if you added carbon to the compound, you'd have atoms of sodium, chlorine, and carbon floating around in water. To separate them would be quite easy.
Friday, September 14, 2012
Lesson 24
(I went into detail in this summary because the lesson was quite confusing in places for some people, I think)
In Lesson 24, we went back to idenfitying patterns within the periodic table and discovered that it's divided into four sections: an "S" block, a "P" block, a "D" block, and an "F" block. S, P, D, and F are letters chemist use to describe the subshells of electron shells within an atom. If that doesn't make sense, subshells are essentially the smaller rings (the "clouds" of space) between the official shell rings, which we typically see in Bohr models. Here's a nifty illustration of that, where blue rings represent the official shells:
You can write how many electrons lie in each subshell like so:
In Lesson 24, we went back to idenfitying patterns within the periodic table and discovered that it's divided into four sections: an "S" block, a "P" block, a "D" block, and an "F" block. S, P, D, and F are letters chemist use to describe the subshells of electron shells within an atom. If that doesn't make sense, subshells are essentially the smaller rings (the "clouds" of space) between the official shell rings, which we typically see in Bohr models. Here's a nifty illustration of that, where blue rings represent the official shells:
Easier? I hope.
The S subshell can hold up to 2 electrons, the P up to 6, the D up to 10, and the F up to fourteen. The F block/subshells are the lanthanides and actinides on the periodic table. You know how many subshells an atom has by where it's located on the periodic table. For example:
- Period 1: S subshell, nothing more
- Period 2: S and P subshells
- Period 3: S and P subshells
- Period 4: S, P, and D subshells (you have now included the transition metals, the "D" block.
- Period 5: S, P, and D subshells
- Period 6: S, P, D, and F subshells (the lanthanides would be found in period 6. Include the F shell)
- Period 7: S, P, D, and F subshells (the actinides are here; include the F shell.)
As you can see, as your period # increases, you have more shells and subshells, and that means that you have bigger atoms, which is why elements in the lanthanides/actinides, like Uranium, are so unstable and decay.
You can write how many electrons lie in each subshell like so:
- [Element symbol] 1s^2s^2p^3s^3p^4s^4p^4d^
As stated in one of my earlier summaries, the ^ symbol stands for the superscript, in this case the number of electrons in the subshell. It is not to be confused with a coefficient, since it's written small and above the number.
Problems:
Lessons 21 and 22
(I'll just combine the two into one summary.)
In Lesson 21, we learned more about ionic compounds, diving further into understanding how they work with a simple card game in which one has 8 cards, all numbered 1 to 7, with a goal to make a total # of 8 "valence electrons" out of two, three, or four cards whilst also creating an ionic compound between a metal and a nonmetal. While the game was easy, repeatedly drawing a card with a 7 from it on the deck was awful, haha. In Lesson 22, we played another card game, this time centered around polyatomic ions. Polyatomic ions are just what their name suggests: ions with multiple atoms in them. They have a charge. Common polyatomic ions include CO3 (carbonate), NH4 (ammonium), OH (hydroxide), and SO4 (sulfate). The goal of our second game was to create a polyatomic compound with two, three, four, or five cards. The compounds had to include a positively-charged cation (which was usually a single element) and a negatively-charged anion (which was usually the polyatomic ions.) We had to snatch up more cards if needed to balance out our own compounds.
Lesson 21 Problems:
1.) Explain how to use the periodic table to determine the charges on ions. As you get closer to the noble gases on the table, your charge becomes more and more negative. As you get closer to group 1A, your charges become more positive.
7.) Predict the formulas for ionic compounds between the following metals and nonmetals:
A.) Al and Br Al3Br
B.) Al and S AlS2
C.) Al and As AlAs
D.) Na and S NaS2
E.) Ca and S CaS
F.) Ga and S GaS2
Lesson 22 Problems:
1.) What is a polyatomic ion? A polyatomic ion is an ion that has multiple atoms in it. It has a charge, and that charge is usually negative.
3.) Write the names of the following compounds:
A.) NH4Cl Ammonium chloride
B.) K2SO4 Potassium sulfate
C.) Al(OH)3 Aluminum hydroxide
D.) MgCO3 Magnesium carbonate
In Lesson 21, we learned more about ionic compounds, diving further into understanding how they work with a simple card game in which one has 8 cards, all numbered 1 to 7, with a goal to make a total # of 8 "valence electrons" out of two, three, or four cards whilst also creating an ionic compound between a metal and a nonmetal. While the game was easy, repeatedly drawing a card with a 7 from it on the deck was awful, haha. In Lesson 22, we played another card game, this time centered around polyatomic ions. Polyatomic ions are just what their name suggests: ions with multiple atoms in them. They have a charge. Common polyatomic ions include CO3 (carbonate), NH4 (ammonium), OH (hydroxide), and SO4 (sulfate). The goal of our second game was to create a polyatomic compound with two, three, four, or five cards. The compounds had to include a positively-charged cation (which was usually a single element) and a negatively-charged anion (which was usually the polyatomic ions.) We had to snatch up more cards if needed to balance out our own compounds.
Lesson 21 Problems:
1.) Explain how to use the periodic table to determine the charges on ions. As you get closer to the noble gases on the table, your charge becomes more and more negative. As you get closer to group 1A, your charges become more positive.
7.) Predict the formulas for ionic compounds between the following metals and nonmetals:
A.) Al and Br Al3Br
B.) Al and S AlS2
C.) Al and As AlAs
D.) Na and S NaS2
E.) Ca and S CaS
F.) Ga and S GaS2
Lesson 22 Problems:
1.) What is a polyatomic ion? A polyatomic ion is an ion that has multiple atoms in it. It has a charge, and that charge is usually negative.
3.) Write the names of the following compounds:
A.) NH4Cl Ammonium chloride
B.) K2SO4 Potassium sulfate
C.) Al(OH)3 Aluminum hydroxide
D.) MgCO3 Magnesium carbonate
Tuesday, September 11, 2012
Lesson 20
As lesson 19 told us, elements bond with one another in a fashion that creates a neutral charge (0.) This requires the presence of cations, positively charged atoms, and anions, negatively charged, and when we have a scenario like this, we get an ionic bond. Ionic bonds typically occur between metals and nonmetals in the periodic table. The electrons in ionic compounds are "stolen" by the atom that has more valence electrons in order to create its full outer shell, and the other atom tags along. When you have an ionic compound between a metal and a nonmetal, you change the ending of the nonmetal's name to -ide. For example, NaCl is sodium chloride, not sodium chlorine.
Problems:
2.) How does the rule of zero charge help you predict the formula of an ionic compound? You can look at the two atoms you are presented with and consider their charges. If Lithium (Li) has a charge of +1, you would write it as Li^+1 (where the ^ tells you that +1 should be a superscript). If You wished to combine it with Fluorine, F, which has a negative charge, you would write the compound as Li^+1F^-1. An easy trick to use is to put the superscript (little number above) of the Fluorine atom as the subscript (little number below) of the Lithium atom, which would tell you that you only had 1 atom of Lithium. In this, you have a negative charged and a balanced chemical compound.
7.) Explain why these compounds do not form:
a.) NaCl2 - If this compound occured, it would not be balanced because it would have a negative charge. In other words, you would have too many chlorine atoms and your delicious table salt would be no more.
b.) CaCl - You would have a great deal of trouble balancing this one, since the chlorine atom, with 7 valence electrons, cannot accommodate Ca's 2. You'd have to give and take Ca and Cl atoms until you came up with a net charge of 0.
c.) AlO - Same with CaCl. You would have too many charges in the aluminum atom to fit with the oxygen atom and matching the charges would be tedious.
Problems:
2.) How does the rule of zero charge help you predict the formula of an ionic compound? You can look at the two atoms you are presented with and consider their charges. If Lithium (Li) has a charge of +1, you would write it as Li^+1 (where the ^ tells you that +1 should be a superscript). If You wished to combine it with Fluorine, F, which has a negative charge, you would write the compound as Li^+1F^-1. An easy trick to use is to put the superscript (little number above) of the Fluorine atom as the subscript (little number below) of the Lithium atom, which would tell you that you only had 1 atom of Lithium. In this, you have a negative charged and a balanced chemical compound.
7.) Explain why these compounds do not form:
a.) NaCl2 - If this compound occured, it would not be balanced because it would have a negative charge. In other words, you would have too many chlorine atoms and your delicious table salt would be no more.
b.) CaCl - You would have a great deal of trouble balancing this one, since the chlorine atom, with 7 valence electrons, cannot accommodate Ca's 2. You'd have to give and take Ca and Cl atoms until you came up with a net charge of 0.
c.) AlO - Same with CaCl. You would have too many charges in the aluminum atom to fit with the oxygen atom and matching the charges would be tedious.
Lessons 18 and 19
Lesson 18:
This lesson gave us a closer look at the patterns that occur in the periodic table. We notice repetition in the number of electron shells in an atom of an element as well as how many valence electrons n element has. Substances in the same group usually have the same number of valence electrons, while elements in the same periods (the horizontal rows) usually have the same number of electron shells. We call the apparatus in which electrons float a shell when we diagram an atom, but when we actually look at an atom, they collect in "clouds" around the nucleus--a topic for a different time. As you move up and down the periods (NOT right to left), the number of shells increases or decreases. As you move right to left through the groups, (1A, 2A, 3A, etc.) you see the number of valence electrons begin to increase until you reach the noble gases.
Problems:
3.) What do Be, Mg, and Ca all have in common? All three elements are found in Group 2A of the periodic table. They have two valence electrons and would probably bond best with 6-valence halogens like O, S, and Se.
8.) For element 50, answer:
a.) Name, symbol, group #: Tin, Sn, Group 4A
b.) Number of protons: 50
c.) Number of neutrons: 50 (roughly, in a neutral atom)
d.) Number of electrons in a neutral atom: 50
e.) Number of valence electrons in a neutral atom: 4
f.) Number of core electrons in a neutral atom: 46
g.) Three other elements w/ same # of valence electrons: Ge (Germanium), Si (Silicon), and C (Carbon).
Lesson 19:
In this lesson, which talked about chemical stability of elements, we learned that some atoms bond more readily than others. For example, the noble gases do not easily bond with other elements because they have a full set of valence electrons (usually 8), whereas the elements in Group 1A of the periodic table need 7 electrons and will bond with just about any halogen to gain a stuffed outer shell. We can pinpoint a section of the table where it's easier for atoms to gain their electrons rather than give them up. For example, it's easier for an oxygen atom, which has 6 valence electrons, to gain 2 rather than deal out those 6, whereas an atom of lithium, with just 1 valence electron, would be better off relinquishing it. Elements usually bond in set ratios to achieve an overall neutral charge, with one atom being positive, a cation, and the other being negative, an anion.
(Here's a nifty tip: if you have trouble remembering the difference between cations and anions, think: anion = "a negative ion". The 't' in cation looks like a plus sign, so cations are positively charged!)
Problems:
2.) Explain what is meant by "noble gas envy". Elements that sit more to the left of the periodic table have a lower number of valence electrons and yearn for a full outer shell, which is why they bond so quickly with other atoms. Every element wants to look like a noble gas, with those perfect 8 electrons.
11.) What is the symbol of an ion with 22 protons, 24 neutrons, and 18 electrons? Ti, Titanium, has 22 protons and, in this scenario, would be positively charged.
12.) When chlorine gains an electron to become a chloride ion with a -1 charge, it ends up with the electron arrangement of argon. Why doesn't it become an argon atom? The chlorine atom originally had 7 valence electrons, and by gaining one, it succeeded in resembling a noble gas--argon. However, its identity did not change, because the only way chlorine could become argon would be if the number of protons increased by 1.
This lesson gave us a closer look at the patterns that occur in the periodic table. We notice repetition in the number of electron shells in an atom of an element as well as how many valence electrons n element has. Substances in the same group usually have the same number of valence electrons, while elements in the same periods (the horizontal rows) usually have the same number of electron shells. We call the apparatus in which electrons float a shell when we diagram an atom, but when we actually look at an atom, they collect in "clouds" around the nucleus--a topic for a different time. As you move up and down the periods (NOT right to left), the number of shells increases or decreases. As you move right to left through the groups, (1A, 2A, 3A, etc.) you see the number of valence electrons begin to increase until you reach the noble gases.
Problems:
3.) What do Be, Mg, and Ca all have in common? All three elements are found in Group 2A of the periodic table. They have two valence electrons and would probably bond best with 6-valence halogens like O, S, and Se.
8.) For element 50, answer:
a.) Name, symbol, group #: Tin, Sn, Group 4A
b.) Number of protons: 50
c.) Number of neutrons: 50 (roughly, in a neutral atom)
d.) Number of electrons in a neutral atom: 50
e.) Number of valence electrons in a neutral atom: 4
f.) Number of core electrons in a neutral atom: 46
g.) Three other elements w/ same # of valence electrons: Ge (Germanium), Si (Silicon), and C (Carbon).
Lesson 19:
In this lesson, which talked about chemical stability of elements, we learned that some atoms bond more readily than others. For example, the noble gases do not easily bond with other elements because they have a full set of valence electrons (usually 8), whereas the elements in Group 1A of the periodic table need 7 electrons and will bond with just about any halogen to gain a stuffed outer shell. We can pinpoint a section of the table where it's easier for atoms to gain their electrons rather than give them up. For example, it's easier for an oxygen atom, which has 6 valence electrons, to gain 2 rather than deal out those 6, whereas an atom of lithium, with just 1 valence electron, would be better off relinquishing it. Elements usually bond in set ratios to achieve an overall neutral charge, with one atom being positive, a cation, and the other being negative, an anion.
(Here's a nifty tip: if you have trouble remembering the difference between cations and anions, think: anion = "a negative ion". The 't' in cation looks like a plus sign, so cations are positively charged!)
Problems:
2.) Explain what is meant by "noble gas envy". Elements that sit more to the left of the periodic table have a lower number of valence electrons and yearn for a full outer shell, which is why they bond so quickly with other atoms. Every element wants to look like a noble gas, with those perfect 8 electrons.
11.) What is the symbol of an ion with 22 protons, 24 neutrons, and 18 electrons? Ti, Titanium, has 22 protons and, in this scenario, would be positively charged.
12.) When chlorine gains an electron to become a chloride ion with a -1 charge, it ends up with the electron arrangement of argon. Why doesn't it become an argon atom? The chlorine atom originally had 7 valence electrons, and by gaining one, it succeeded in resembling a noble gas--argon. However, its identity did not change, because the only way chlorine could become argon would be if the number of protons increased by 1.
Monday, September 10, 2012
Lesson 17
In this lesson, we discovered that some atoms, when set aflame, burn bright colors. Certain properties within the elements cause this spectral sight, and it can be used in experiments to determine if a metal is present in a compound. Strontium compounds will burn a vibrant red, while sodium produces a yellow-orange hue. Copper takes blue-green, while potassium burns either lilac or a light pink. Colors appear only if a metal is present; nonmetals don't give us much to look at.
Problems:
What flame colors would be produced by these compounds? Explain.
a.) Na2CO3 - Yellow-orange, because sodium is present.
b.) Ba(OH)2 - Blue-green...? Barium is present, and that's what color of flame it produces.
c.) KOH - Pink-lilac! This is one of the substances we tested; potassium gives it its color.
d.) K2CO3 - Pink-lilac again, because of the potassium.
e.) BaO - Blue-green because of the barium in the compound.
Imagine you were in charge of creating a red and purple fireworks display. Name two combinations of compounds you could use.
Strontium, as stated above, produces a vibrant firetruck red color, so you'd probably want some strontium compounds in your firework mix. Lithium would also do, so you could use lithium sulfate. As for the purple fireworks, you could use potassium compounds, since potassium gives off a lilac-y color when burned.
Problems:
What flame colors would be produced by these compounds? Explain.
a.) Na2CO3 - Yellow-orange, because sodium is present.
b.) Ba(OH)2 - Blue-green...? Barium is present, and that's what color of flame it produces.
c.) KOH - Pink-lilac! This is one of the substances we tested; potassium gives it its color.
d.) K2CO3 - Pink-lilac again, because of the potassium.
e.) BaO - Blue-green because of the barium in the compound.
Imagine you were in charge of creating a red and purple fireworks display. Name two combinations of compounds you could use.
Strontium, as stated above, produces a vibrant firetruck red color, so you'd probably want some strontium compounds in your firework mix. Lithium would also do, so you could use lithium sulfate. As for the purple fireworks, you could use potassium compounds, since potassium gives off a lilac-y color when burned.
Friday, September 7, 2012
Lessons 15 and 16
Lesson 15:
In nuclear reactions, which include the nucleus of an atom, energy is released. Some elements turn into other elements by processes called alpha and beta decay. In alpha decay, unstable elements emit alpha particles (helium atoms) in order to stabilize themselves. The mass number of the original element is decreased by 4 and the atomic number by 2. The change in atomic number results in a change in the element's identity. In beta decay, an element also changes because a neutron from the original element turns into a proton and a neutron and the proton changes the atomic number. The electron produced from beta decay is emitted and floats around, doing damage, until it finds another element to bind with. Both nuclear reactions release harmful gamma radiation.
Problems:
3.) What type of radiation is most harmful to living things: alpha, beta, or gamma radiation? Why? Gamma radiation is emitted from both alpha and beta decay, but it is the most harmful of the three, with beta decay coming in at a close second. Gamma radiation can cause mutation in organisms, resulting in cancer or severe deformities. A good example of this would be the medical complications that survivors of the Chernobyl meltdown sustained.
4.) Explain why the mass of an atom changes when an alpha particle is emitted. When an atom emits an alpha particle during alpha decay, it's essentially giving off a helium atom--so, two protons and four neutrons. The mass number, which (if being recorded using nuclear notation) is the top number, decreases by four and the atomic number by two, hence why a new element is created. You're losing particles, so you're losing mass.
Lesson 16:
Elements are formed by nuclear reactions which, simply put, are chemical reactions involving the nucleus of an atom. Examples of nuclear reactions include radioactive decay (beta and alpha), fission, and fusion, all of which release some tremendous energy. From these reactions, new elements are formed, but some formations simply cannot occur on earth. For example, gold formation requires so much heat and energy that it isn't humanly possible to create it in a lab. It must be formed in supernovas, which are the explosions (deaths, if you will) of stars.
Problems:
1.) Describe four processes that result in new elements being formed. Four nuclear processes are alpha decay, where an unstable element gives off a helium atom (alpha particle) and transforms to a new, more stable element, beta decay, where an unstable element shoots off a particle that splits into a proton and an electron, fission, where the nucleus of an atom is split apart resulting in tremendous, often harmful amounts of energy, and fusion, where two different atoms of elements are combined to form one new, larger one.
2.) What happens in a nuclear chain reaction? In a nuclear chain reaction, particles shot off by an unstable element split the nuclei of nearby atoms, and from those nuclei, more particles are emitted to travel around and destroy other things until they can find something to bind to. Essentially, it's one atom splitting after another in a high-speed process.
In nuclear reactions, which include the nucleus of an atom, energy is released. Some elements turn into other elements by processes called alpha and beta decay. In alpha decay, unstable elements emit alpha particles (helium atoms) in order to stabilize themselves. The mass number of the original element is decreased by 4 and the atomic number by 2. The change in atomic number results in a change in the element's identity. In beta decay, an element also changes because a neutron from the original element turns into a proton and a neutron and the proton changes the atomic number. The electron produced from beta decay is emitted and floats around, doing damage, until it finds another element to bind with. Both nuclear reactions release harmful gamma radiation.
Problems:
3.) What type of radiation is most harmful to living things: alpha, beta, or gamma radiation? Why? Gamma radiation is emitted from both alpha and beta decay, but it is the most harmful of the three, with beta decay coming in at a close second. Gamma radiation can cause mutation in organisms, resulting in cancer or severe deformities. A good example of this would be the medical complications that survivors of the Chernobyl meltdown sustained.
4.) Explain why the mass of an atom changes when an alpha particle is emitted. When an atom emits an alpha particle during alpha decay, it's essentially giving off a helium atom--so, two protons and four neutrons. The mass number, which (if being recorded using nuclear notation) is the top number, decreases by four and the atomic number by two, hence why a new element is created. You're losing particles, so you're losing mass.
Lesson 16:
Elements are formed by nuclear reactions which, simply put, are chemical reactions involving the nucleus of an atom. Examples of nuclear reactions include radioactive decay (beta and alpha), fission, and fusion, all of which release some tremendous energy. From these reactions, new elements are formed, but some formations simply cannot occur on earth. For example, gold formation requires so much heat and energy that it isn't humanly possible to create it in a lab. It must be formed in supernovas, which are the explosions (deaths, if you will) of stars.
Problems:
1.) Describe four processes that result in new elements being formed. Four nuclear processes are alpha decay, where an unstable element gives off a helium atom (alpha particle) and transforms to a new, more stable element, beta decay, where an unstable element shoots off a particle that splits into a proton and an electron, fission, where the nucleus of an atom is split apart resulting in tremendous, often harmful amounts of energy, and fusion, where two different atoms of elements are combined to form one new, larger one.
2.) What happens in a nuclear chain reaction? In a nuclear chain reaction, particles shot off by an unstable element split the nuclei of nearby atoms, and from those nuclei, more particles are emitted to travel around and destroy other things until they can find something to bind to. Essentially, it's one atom splitting after another in a high-speed process.
Thursday, September 6, 2012
Lesson 13
Lesson 13:
Today's lesson touched on everything about isotopes: what they are, how common they are based on certain elements, and how there's no such thing as a "regular" atom of an element and an isotope. The quantity of a certain isotope that appears in a sample of an element is referred to as the "natural percent abundance". You can write isotope names with hyphen notation and nuclear notation:
Boron-10 is B-10 in hyphen notation.
Boron-10 is 10/5 B in nuclear notation, where 10 represents the mass # and 5 is the atomic
number.
Problems:
2.) Explain the difference between the atomic masses listed on the periodic table and the mass of an atom. The mass of a single atom can be calculated by rounding the atomic mass on the table to the nearest whole number (I think, does anyone agree?) If that's not it, then the mass is simply the number of protons and neutrons in a neutrally-charged atom. The atomic mass on the periodic table states the average mass of the most common isotope(s) of an element.
9.) Which isotope of nitrogen is found in nature? Explain. The isotope 14/7 N is found in nature. It is the only option of those given that stays true to nitrogen's identity, with 7 protons.
Today's lesson touched on everything about isotopes: what they are, how common they are based on certain elements, and how there's no such thing as a "regular" atom of an element and an isotope. The quantity of a certain isotope that appears in a sample of an element is referred to as the "natural percent abundance". You can write isotope names with hyphen notation and nuclear notation:
Boron-10 is B-10 in hyphen notation.
Boron-10 is 10/5 B in nuclear notation, where 10 represents the mass # and 5 is the atomic
number.
Problems:
2.) Explain the difference between the atomic masses listed on the periodic table and the mass of an atom. The mass of a single atom can be calculated by rounding the atomic mass on the table to the nearest whole number (I think, does anyone agree?) If that's not it, then the mass is simply the number of protons and neutrons in a neutrally-charged atom. The atomic mass on the periodic table states the average mass of the most common isotope(s) of an element.
9.) Which isotope of nitrogen is found in nature? Explain. The isotope 14/7 N is found in nature. It is the only option of those given that stays true to nitrogen's identity, with 7 protons.
Tuesday, September 4, 2012
Lesson 12: Atoms in Numbers
Today we learned about the numbers used to describe certain atoms and elements. We once again chanted the phrase "atomic number, number of protons" to make sure everyone understood it, and then we dealt with how to find different quantities within atoms (such as number of protons, number of neutrons, number of electrons, and so on). The atomic mass can be expressed in two ways: as a whole number, which is found by adding the protons and neutrons, and by the decimal listed on the periodic table, which is the element's exact mass in amu units. If you subtract the number of protons from the exact atomic mass, you can determine the number of neutrons in the nucleus, and if this number is a decimal, round it to the nearest whole number. Then you have an isotope! The exact mass on the table is the mass of the element's most common isotope. Protons, neutrons, and electrons will not always be the same as one another, but in a neutrally-charged atom (where neither positive nor negative charges dominate) they are.
Problems for Lesson 12:
2.) What does the atomic mass tell you? The number listed alongside an element in the table is the atomic mass, and it tells you the average mass of the protons and neutrons within the nucleus of an element of that atom. Usually that number is listed as a decimal, which represents the average mass of the most commonly observed isotope of an atom.
4.) If you wanted to identify an element, what one piece of information would you ask for? The only piece of information you would need to identify an element is the atomic number. This identifies the number of protons, and if you change the protons, that means you change the element!
5.) Why does an atom of carbon (C) have a larger atomic mass than an atom of boron (B) if they have the same number (6) of neutrons? Boron and carbon do not have the same atomic number. With one having more or less protons than the other, it doesn't matter if they have the same number of neutrons. Protons carry more mass in the nucleus.
Problems for Lesson 12:
2.) What does the atomic mass tell you? The number listed alongside an element in the table is the atomic mass, and it tells you the average mass of the protons and neutrons within the nucleus of an element of that atom. Usually that number is listed as a decimal, which represents the average mass of the most commonly observed isotope of an atom.
4.) If you wanted to identify an element, what one piece of information would you ask for? The only piece of information you would need to identify an element is the atomic number. This identifies the number of protons, and if you change the protons, that means you change the element!
5.) Why does an atom of carbon (C) have a larger atomic mass than an atom of boron (B) if they have the same number (6) of neutrons? Boron and carbon do not have the same atomic number. With one having more or less protons than the other, it doesn't matter if they have the same number of neutrons. Protons carry more mass in the nucleus.
Sunday, September 2, 2012
Lessons 6, 9, and 10
The Basics of the Periodic Table:
These three lessons were mainly about the periodic table. We learned the factors that went into creating the table and why it's set up in the way that it is. We identified patterns within the groups/families in the table and determined where an element would be placed based off its properties. We briefly covered the importance of reactivity in organizing the table and went through the names of the groups (alkali, alkaline-earth, transition, halogen, and noble gas).
Lesson 6:
This lesson touched on both what an element is and how it can create compounds with other elements. Elements are represented by a capital and lowercase letter called a chemical symbol. In a compound, elements have to be combined in a specific ratio to produce the right substance afterwards. Sometimes you can end up with crazy colored substances after a reaction. Compounds can be in solid, liquid, or gas form.
Problems:
2.) What is meant by "physical form"? A physical form is a fancier way of saying 'solid', 'liquid', or 'gas'. It describes the state that matter is in at a given time or before/after a reaction.
3.) How many elements are included in the chemical formula for sodium nitrate, NaNO3? There are three elements here, in a given ratio. Na is sodium, N is nitrogen, and O is oxygen. There are 3 oxygen molecules, one nitrogen molecule, and one sodium molecule.
4.) What is the difference between NaOH(s) and NaOH(aq)? Both compounds are sodium hydroxide. The biggest difference is what lies in the parentheses--the (s) and the (aq). The s means that it's solid sodium hydroxide. The aq implies that the solid sodium hydroxide has been dissolved in water.
Lesson 9:
A man by the name of Dmitri Mendeleyev created the periodic table of elements. He organized elements by their reactivity and the number of valence electrons in their outer electron shells. Some elements within the table are placed right next to, or above and below each other because they react similarly with certain substances (i.e. water), and as you compare the reactions of different groups you can get starkly different results. Holes were left in Mendeleyev's "prototype" periodic table to make room for elements that existed but hadn't yet been discovered.
Problems:
2.) Which element would carbon (C) be more similar to: nitrogen (N), oxygen (O), or silicon (S)? Carbon is more similar to silicon (Si) than any of the other elements listed. If you look at the periodic table, Si lies just beneath C, and they are in the same group, which means that they have the same number of valence electrons in their outer shell and that they react in a similar way when combined with water. N and O are near C, but they are in different groups which means that they're subject to react differently than it.
4.) Look up the properties of iron, barium, or phosphorus and explain why nails are made of iron and not barium or phosphorus.
Properties of iron: reacts with water to oxidate and form rust but does not explode. Is generally sturdy.
Properties of barium: Reacts with almost all nonmetals, forming poisonous substances, and reacts vigorously with water to release hydrogen gas.
Properties of phosphorus: Conducts electricity, almost never found in its pure form in nature, somewhat combustible (hence why we use it in matches)
If we made nails out of anything other than iron, we would probably have some serious infrastructure problems on our hands. That, or health hazards.
Lesson 10:
Elements are placed in the periodic table strategically. Violently reactive substances, like the alkali and alkaline-earth metals, find homes on the left side of the table, while elements that barely react at all (or that have to be forcefully combined by man) take up the right side. Elements that are somewhat reactive but relatively boring fill the center chunk of the table and make up the "transition metals". A zig-zag line toward the right side of the table splits the metals and nonmetals apart, and the elements that hug it we call metalloids.
Problems:
1.) Describe how reactivity changes as you go down Group 1A. Group 1A can also be called the alkali metal group, which means that all of its elements react violently with water. some even produce a flame. Hydrogen sits on top of the group and is usually emitted from chemical reactions involving the other elements in Group 1A. As you go farther down the period, the reactivity increases and your experiments become more dangerous. For example, compare the reaction between sodium (Na) and water to the reaction between cesium (Cs) and water. One produces a bigger spark and can sometimes cause the apparatus in which it's reacting to shatter.
5.) Which of the following elements are solid: fluorine (F), oxygen (O), titanium (Ti), potassium (K), lead (Pb), silicon (Si)? Titanium, potassium, lead, and silicon are all solids.
8.) Which elements can you make jewelry out of, and why? Copper (Cu), neon (Ne), sodium (Na), platinum (Pt). Well, good luck finding a way to make jewelry out of neon. It's a noble gas, which means it will not combine with any other element and it's a gas, which means it's not malleable. As for sodium, ever time you got your piece of jewelry wet, it would sizzle and fizz. Sodium is also soft enough to cut with a knife, so your jewelry would probably bend and/or break all the time. Copper is very malleable but also sturdy, being a solid. It doesn't react readily with water. Platinum is a transition metal (one of those boring elements) so it would also be good for jewelry.
These three lessons were mainly about the periodic table. We learned the factors that went into creating the table and why it's set up in the way that it is. We identified patterns within the groups/families in the table and determined where an element would be placed based off its properties. We briefly covered the importance of reactivity in organizing the table and went through the names of the groups (alkali, alkaline-earth, transition, halogen, and noble gas).
Lesson 6:
This lesson touched on both what an element is and how it can create compounds with other elements. Elements are represented by a capital and lowercase letter called a chemical symbol. In a compound, elements have to be combined in a specific ratio to produce the right substance afterwards. Sometimes you can end up with crazy colored substances after a reaction. Compounds can be in solid, liquid, or gas form.
Problems:
2.) What is meant by "physical form"? A physical form is a fancier way of saying 'solid', 'liquid', or 'gas'. It describes the state that matter is in at a given time or before/after a reaction.
3.) How many elements are included in the chemical formula for sodium nitrate, NaNO3? There are three elements here, in a given ratio. Na is sodium, N is nitrogen, and O is oxygen. There are 3 oxygen molecules, one nitrogen molecule, and one sodium molecule.
4.) What is the difference between NaOH(s) and NaOH(aq)? Both compounds are sodium hydroxide. The biggest difference is what lies in the parentheses--the (s) and the (aq). The s means that it's solid sodium hydroxide. The aq implies that the solid sodium hydroxide has been dissolved in water.
Lesson 9:
A man by the name of Dmitri Mendeleyev created the periodic table of elements. He organized elements by their reactivity and the number of valence electrons in their outer electron shells. Some elements within the table are placed right next to, or above and below each other because they react similarly with certain substances (i.e. water), and as you compare the reactions of different groups you can get starkly different results. Holes were left in Mendeleyev's "prototype" periodic table to make room for elements that existed but hadn't yet been discovered.
Problems:
2.) Which element would carbon (C) be more similar to: nitrogen (N), oxygen (O), or silicon (S)? Carbon is more similar to silicon (Si) than any of the other elements listed. If you look at the periodic table, Si lies just beneath C, and they are in the same group, which means that they have the same number of valence electrons in their outer shell and that they react in a similar way when combined with water. N and O are near C, but they are in different groups which means that they're subject to react differently than it.
4.) Look up the properties of iron, barium, or phosphorus and explain why nails are made of iron and not barium or phosphorus.
Properties of iron: reacts with water to oxidate and form rust but does not explode. Is generally sturdy.
Properties of barium: Reacts with almost all nonmetals, forming poisonous substances, and reacts vigorously with water to release hydrogen gas.
Properties of phosphorus: Conducts electricity, almost never found in its pure form in nature, somewhat combustible (hence why we use it in matches)
If we made nails out of anything other than iron, we would probably have some serious infrastructure problems on our hands. That, or health hazards.
Lesson 10:
Elements are placed in the periodic table strategically. Violently reactive substances, like the alkali and alkaline-earth metals, find homes on the left side of the table, while elements that barely react at all (or that have to be forcefully combined by man) take up the right side. Elements that are somewhat reactive but relatively boring fill the center chunk of the table and make up the "transition metals". A zig-zag line toward the right side of the table splits the metals and nonmetals apart, and the elements that hug it we call metalloids.
Problems:
1.) Describe how reactivity changes as you go down Group 1A. Group 1A can also be called the alkali metal group, which means that all of its elements react violently with water. some even produce a flame. Hydrogen sits on top of the group and is usually emitted from chemical reactions involving the other elements in Group 1A. As you go farther down the period, the reactivity increases and your experiments become more dangerous. For example, compare the reaction between sodium (Na) and water to the reaction between cesium (Cs) and water. One produces a bigger spark and can sometimes cause the apparatus in which it's reacting to shatter.
5.) Which of the following elements are solid: fluorine (F), oxygen (O), titanium (Ti), potassium (K), lead (Pb), silicon (Si)? Titanium, potassium, lead, and silicon are all solids.
8.) Which elements can you make jewelry out of, and why? Copper (Cu), neon (Ne), sodium (Na), platinum (Pt). Well, good luck finding a way to make jewelry out of neon. It's a noble gas, which means it will not combine with any other element and it's a gas, which means it's not malleable. As for sodium, ever time you got your piece of jewelry wet, it would sizzle and fizz. Sodium is also soft enough to cut with a knife, so your jewelry would probably bend and/or break all the time. Copper is very malleable but also sturdy, being a solid. It doesn't react readily with water. Platinum is a transition metal (one of those boring elements) so it would also be good for jewelry.
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