Topic 6 - shapes of Molecules and Intermolecular Forces

Question 1

Bonding pairs

Answer 1

Involved in forming covalent bonds with other atoms

Question 2

Lone pairs

Answer 2

Not involved in bonding and remain on the central atom

Question 3

Why do molecules adopts a shape due to the numbers of bonding pairs?

Answer 3

To minimise the repulsion between its electron pairs due to their negative charge

Question 4

Electron pair repulsion theory

Answer 4

1. electron pairs, whether bonding
   or lone, repel eachother
2. Lone pairs cause more repulsion
   than bonding as they are closer
   to the nucleus
3. Electron pairs arrange
   themselves as far apart as
   possible to minimise repulsion

Question 5

Lone pairs repulsion

Answer 5

• occupies more space
• affects molecules shape but
  compressing bond angles

Question 6

Bond angles

Answer 6

Decreases and the lone pairs increases

Question 7

Linear

Answer 7

• 2 bonding pairs
• 0 lone pairs
• 180 angle

Question 8

Bent

Answer 8

• 2 bond pairs
• 2 lone pairs
• 104.3 angle

Question 9

Trigonal planar

Answer 9

• 3 bond pairs
• o lone pairs
• 120 angle

Question 10

Trigonal pyramidal

Answer 10

• 3 bond pairs
• 1 lone pair
• 107 angle

Question 11

Tetrahedral

Answer 11

• 4 bond pairs
• o lone pairs
• 109.5 angle

Question 12

Trigonal bipyramidal

Answer 12

-5 bond pairs
- 0 lone pairs
- 120 & 90 angles

Question 13

Octahedral

Answer 13

• 6 bond pairs
• 0 lone pairs
• 90 angles

Question 14

linear example

Answer 14

BeCL2

Question 15

Bent example

Answer 15

H20

Question 16

Trigonal planar example

Answer 16

BF3

Question 17

Trigonal pyramidal example

Answer 17

NH3

Question 18

Tetrahedral example

Answer 18

CH4

Question 19

Trigonal bipyramidal example

Answer 19

PCl5

Question 20

Octahedral example

Answer 20

SF6