Lessons 13 and 15

Today in chemistry we learned about isotopes and nuclear notation. Isotopes are variants of the one element. The element will have the same number of protons but can have different numbers of neutrons. We also learned about nuclear notation, which is the different ways writing an element's isotope. There are two ways to write it which are pictured below. In lesson 15 we learned about alpha and beta decay. Alpha decay occurs when an element loses 4 protons and 2 neutrons (helium) to become more stable. Beta decay is when in an attempt to become more stable a neutron turns into a proton and then loses and electron. Both types of decay emit energy.







Lesson 13 Practice Problems

1. Atomic number is the number of protons that are found in the nucleus of an element. Atomic mass is the number of protons plus the number of neutrons found in the nucleus.
4A. If the atom has no charge then, 9 protons, 12 neutrons and 9 electrons
6A. 30.7973
6B. 15
6C. I would say the most common isotope would be P-31 because that is the closest whole number to the average atomic mass.

Lesson 15 Practice Problems
4. The mass of an atom changes when an alpha particle is emmited because it loses 2 protons. Protons and neutrons make up the mass of the atom so if two protons are lost the mass will shrink.
5. When a beta particle is emmited the mass of an atom does not change because a neutron simply becomes a proton. A neutron is "lost" but a proton is gained so the total mass does not change. An electron is lost but they do not count for mass so it does not affect the mass of an atom.