CHEM 101 Lecture Notes - Lecture 2: Unified Atomic Mass Unit, Phosphide, Electromagnetic Radiation

• School: Ball State University
• Department: Chemistry
• Course: CHEM 101
• Professor: Dr.Emil F.Khisamutdinov

Document Summary

Atom: the smallest most fundamental unit of matter. Element: a substance composed of one type of atom. Compound: made up of 2 or more elements. Tight group of protons and neutrons in the center of atom: electrons are outside of nucleus. Atoms with the same number of protons but different numbers of neutrons. Called shells: n=1,2,3, max # of electrons in shell. Fill levels up from the inside out. Group 1a: 1 electron in outer shell. Group 2a: 2 electrons in outer most shell. Valence electrons: electrons occupying outer most shell. Atoms within the group have the same number of valence electrons but they are in different numbered shells. Full valence shells are particularly stable: table 2-7. Give the elctron arrangement for the elements shown below from the lowest to highest: neon, boron, nitrogen: answer: Are atoms that have lost or gained on or more valence electrons, giving them a net charge. Anything with a charge is an ion.