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.