CHEM101 Study Guide - Trigonal Planar Molecular Geometry, Lone Pair, Square Planar Molecular Geometry

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

Document Summary

Valence electron pairs try to repel each other and maximize the distance between them. e pairs are in bonds unshared e localized between the atoms as far as possible from other pairs (including those in bonds) Need to consider: effect of different atoms. Bond length, polarity may change, but molecular geometry remains approximately the same: # of different e pairs. Geometry does change: unshared e will dictate the geometry but are not used in describing it. Only the position of bonded atoms can be determined accurately. Any bond (single, double or triple) counts as 1 effective pair. This is because the bonded electrons can be localized in the region directly between the atoms. Each unshared pair also counts as 1 effective pair. The difference is that unshared pairs are counted separately while a bond always counts as one, even if it is a multiple bond. X has 4 effective pairs (3 lone + 1 bond)