AP/gen chem compound structures and properties

Boron specialness

Doesn’t need a complete octet

Expanded octets

atoms between period 3-7 can expand an and bond with more than 8 electrons because of Ds

Formal charge

Valence electrons - electrons assigned = formal charge

VSEPR

Valence shell electron pair repulsion theory

Charge clouds repel each other

Terminal atoms move as far away from each other as possible

Results in distinctive shapes

Linear

2 charge clouds, 2 bonds, 0 lone pairs

180°

Triangle planar

3 charge clouds, 3 bonds, 0 lone pairs

120°

Bent

3 charge clouds, 2 bonds, 1 lone pair

120°

Tetrahedral

4 charge clouds, 4 bonds, 0 lone pairs

109.5°

Trigonal pyramidal

4 charge clouds, 3 bonds, 1 lone pairs

109.5°

Super bent

4 charge clouds, 2 bonds, 2 lone pairs

109.5°

Trigonal bipyramidal

5 charge clouds, 5 bonds 0 lone pairs

120°

Seesaw

5 charge clouds, 4 bonds, 1 lone pair

T-shaped

5 charge clouds, 3 bonds, 2 lone pairs

90°

Super linear

5 charge clouds, 2 bonds, 3 lone pairs

180°

Octahedral

6 charge clouds, 6 bonds, 0 lone pairs

90°

Square pyramidal

6 charge clouds, 5 bonds, 1 lone pair

90°

Square planar

6 charge clouds, 4 bonds, 2 lone pairs

90°