CHEM 1127Q Lecture Notes - Lecture 2: Unified Atomic Mass Unit, Mass Number, Atomic Number

• School: UConn
• Department: Chemistry
• Course: CHEM 1127Q
• Professor: Cady

Document Summary

Atomic theory (dalton: no atom disappears or changes in chemical reaction, different combinations form different compounds. Atoms made up of: protons, neutrons, electrons. 8o-2: atomic number = # protons, mass number = # protons + # neutrons, mass - atomic = # neutrons, electrons = #protons - charge (-2 in oxygen means 2 extra electrons) 57fe: how many protons, all iron atoms have 26 protons (atomic number, how many neutrons, 57 - 26 = 31 neutrons, how many electrons, no charge so also 26 electrons (# protons - 0 = 26) Mass = (mass1 x frac1) + (mass2 x frac2) + (mass3 x frac3) Molecular vs empirical formula: molecular: unsimplified - c2h4o6, empirical: simplified -- ch2o3. Molecular elements: diatomic elements, always come in pairs, technically molecules because they are pairs, hofbrincl. Ions: atoms or molecules lose or gain electrons, na --> na+ + e, + 2e- --> o2-