Shapes of Molecules

What is the VSEPR theory?

It predicts the shapes of molecules based on the idea that electrons repel each other.

what is outlined in VSEPR

lone pair- lone pair= greatest repulsion lone pair- bonding pair= medium repulsion bonding pair- bonding pair= smallest repulsion

2 bonding pairs

linear, 180 degrees, all bonding pairs repelled equally

3 bonding pairs

trigonal planar, 120 degrees, all bp repelled equally

4 bonding pairs

tetrahedral, 109.5 degrees, all bp repelled equally

3 bonding pairs 1 lone pair

trigonal pyramidal, 107 degrees; lone pair and bp repel more than 2 bp's, so bp's are pushed closer together

2 bonding pairs 1 lone pair

Non-linear (bent), 117.5 degrees

2 bonding pairs 2 lone pairs

bent, 104.5 degrees; lp,lp repulsion> lp, bp repulsion> bp bp repulsion

5 bonding pairs

trigonal bipyramidal, 90 degrees and 120 degrees; all bp repelled equally

3 bonding pairs 2 lone pairs

trigonal planar, 120 degrees; the repulsion from the lone pairs on one side equalises the repulsion from the lone pair on the other side

6 bonding pairs

Octahedral, 90 degrees, 180 degrees; all bp repelled equally