2.23 - Shapes of Molecules and Ions Flashcards
What does Electron Pair Repulsion Theory state?
That the shape of a molecule or ion is caused by repulsion between the bond and lone pairs of electrons surrounding each atom
How do the electron pairs arrange themselves?
Such that the repulsion between them is at a minimum
What is the trend in repulsive strength (highest to lowest)
Lone pair - Lone pair -> Lone pair - Bond pair -> Bond pair - Bond pair
What is this theory sometimes also known as?
Valence Shell Electron Pair Repulsion Theory (VSEPR)
What two pieces of information are required to determine the shape of a molecule or ion?
The number of lone pairs and the number of bond pairs
How should multiple bonds be treated?
As though it only contains one pair of electrons
Name the shape given the information:
Bond Pairs - 2
Lone Pairs - 0
Linear
Name the shape given the information:
Bond Pairs - 3
Lone Pairs - 0
Trigonal Planar
Name the shape given the information:
Bond Pairs - 4
Lone Pairs - 0
Tetrahedral
Name the shape given the information:
Bond Pairs - 5
Lone Pairs - 0
Trigonal Bipyramidal
Name the shape given the information:
Bond Pairs - 6
Lone Pairs - 0
Hexagonal
Name the shape given the information:
Bond Pairs - 3
Lone Pairs - 1
Trigonal Pyramidal
Name the shape given the information:
Bond Pairs - 2
Lone Pairs - 2
V-Shaped
What is the bond angle in a linear molecule?
180°
What is the bond angle in a trigonal planar molecule?
120°
