Bond angles and shapes

Question 1

What angle and shape is a molecule with a coordination number of 2?

Answer 1

Linear 180 degrees

Question 2

What angle and shape is a molecule with a coordination number of 3?

Answer 2

Trigonal planar 120 degrees

Question 3

What angle and shape is a molecule with a coordination number of 4?

Answer 3

Tetrahedral 109.5 degrees

Question 4

What angle and shape is a molecule with a coordination number of 5?

Answer 4

Trigonal bipyramidal 120 & 90 degrees

Question 5

What angle and shape is a molecule with a coordination number of 6?

Answer 5

Octahedral 90 degrees

Question 6

What angle and shape is an ammonia molecule (3 bonding pairs 1 lone pair)?

Answer 6

Trigonal pyramidal 107 degrees

Question 7

What angle and shape is a water molecule (2 bonding pairs 2 lone pairs)?

Answer 7

V shape 104.5 degrees

Question 8

Why do tetrahedral and trigonal planar have different bond angles if both have 4 electron pairs?

Answer 8

Pairs of electrons in the outer shell of atoms arrange themselves as far apart as possible to minimise repulsion. Lone pair–lone pair repulsion is greater than lone pair–bond pair repulsion, which is greater than bond pair–bond pair repulsion.

Question 9

What are the 5 steps to calculate the shape of any molecule?

Answer 9

1) Count outer shell e- of the central atom.
2) Add all the e- bonding atoms bring.
3) Add/remove any e- for any charges present.
4) Divide number by 2 to work out electron pairs.
5) Look at the molecule and count bonding and loan pairs.