6.1 Shapes of molecules and ions

Question 1

what is the electron-repulsion theory?

Answer 1

electrons have a negative charge so electron pairs repel each other

the shapes of molecules are determined by the level of repulsion from the electron pairs

electron pairs repel each other as far apart as possible to minimise repulsion

Question 2

in a 3d diagram what is the wedge shape?

Answer 2

plane coming out of the paper

Question 3

in a 3d diagram what is the dotted wedge?

Answer 3

plane going into the paper

Question 4

what are the two types of electron pairs?

Answer 4

bond pairs
lone pairs

Question 5

what is the interaction between a bond pair and a lone pair?

Answer 5

lone pairs repel more strongly than bond pairs

Question 6

what effect does a lone pair have on the bond pairs?

Answer 6

by repelling the bond pairs, the angle between bond pairs decreases

Question 7

by how much does a lone pair decrease the bond angle?

Answer 7

2.5 degrees

Question 8

4 bond
0 lone

Answer 8

tetrahedral
109.5

Question 9

3 bond
1 lone

Answer 9

pyramidal
107

Question 10

2 bond
2 lone

Answer 10

non-linear
104.5

Question 11

2 bond
0 lone

Answer 11

linear
180

Question 12

3 bond
0 lone

Answer 12

trigonal planar
120

Question 13

6 bond
0 lone

Answer 13

octahedral
90