CHEM101 Lecture Notes - Lecture 2: Unified Atomic Mass Unit, New Zealand, Atomic Number

• School: University of Alberta
• Department: Chemistry
• Course: CHEM101
• Professor: Yoram Apelblat

Document Summary

Elements: a first look at the periodic table. Table 2. 2 properties of the three key subatomic particles. * the coulomb (c) is the si unit of charge. The atomic mass unit (amu) equals 1. 66054x10-24 g. Mass of e- = (~ mass of proton) A = mass number; a = z + n. Z = atomic number (the number of protons in the nucleus) N = number of neutrons in the nucleus. We will not go into any other subparticles (left for your physics courses). Different atoms (cid:156) different # of e , protons. An element is composed of a single type of atoms. Atoms with different number of neutrons are called isotopes. Isotopes are atoms of an element with the same number of protons, but a different number of neutrons. In other words, isotopes have the same atomic number, but a different mass number. Isotopes of sodium: 11 e , 11 p+, 12 no.