CHEM 203 Lecture Notes - Electron Affinity, Lone Pair, Formal Charge

• School: UBC
• Department: Chemistry
• Course: CHEM 203
• Professor: All

Document Summary

Lewis structures electron diagram of a covalent system. Length of bonds are: count electrons in the system (valence and any charges, draw the system central atom the one w/ the least electronegativity (never hydrogen) Draw bonds (2 electrons) from central atom to remaining atoms: complete octets w/ lone pairs e. g. b, al, and s, p, i can have expanded octets, assign any formal charge (when applicable) Formal charge = # valence electrons lone pair electrons bond electrons. Remember ex. of carbon, n, o, halogens e. g. co2. 2 o x 6 e- = 12 e- (valence) 4 o = 4 x 6 e- = 24 e- 1s = 1 x 6 e- = 6 e- If you can eliminate formal charges, do it. Vsepr geometry shape w/ the most stability. X = # bonds (covalent double and triple count as one bond) E = # lone pairs on the central atom (only the central atom)