Bonding And Structure

Question 1

How do electron pairs arrange themselves

Answer 1

To minimise repulsion and maximise seperation

Question 2

Strength of repulsion

Answer 2

Lone pair lone pair > lone pair bonding pair > bonding pair bonding pair

Question 3

Shape and angle with 2 bonding pairs 0 lone pairs

Answer 3

Linear

180 degrees

Question 4

Shape and angle with 3 bonding pairs 0 lone pairs

Answer 4

Trigonal planar

120 degrees

Question 5

Shape and angle with 3 bonding pairs 1 lone pairs

Answer 5

Trigonal pyramidal

107 degrees

Question 6

Shape and angle with 2 bonding pairs 2 lone pairs

Answer 6

Bent (v-shape)

104.5 degrees

Question 7

Shape and angle with 5 bonding pairs 0 lone pairs

Answer 7

Trigonal Pyrimidal

120 and 90 degrees

Question 8

Shape and angle with 4 bonding pairs 1 lone pairs

Answer 8

Trigonal pyrimidal

119 and 89 degrees

Question 9

Shape and angle with 3 bonding pairs 2 lone pairs

Answer 9

Trigonal planar

120 or 89 degrees

Question 10

Formula for bond angle with 4 pairs

Answer 10

109.5 minus (number of bonding pairs * 2.5)

Question 11

Qualities of water as a solvent

Answer 11

All 3 intermolecular forces present
Ionic compounds mostly soluble in it

Compounds with hydrogen bonding normally soluble in it

Non-polar solvents insoluble in it

Question 12

Qualities of hexane (or other non-aqueous solvents) as a solvent

Answer 12

Only London forces present

Ionic compounds insoluble in it

Compounds with hydrogen bonding normally insoluble in it

Non-polar solvents soluble in it

Question 13

Why are ionic compounds soluble in water

Answer 13

Water molecules attracted to the ions

Form ion-dipole intersections which release energy

This energy can break bonds between ions and between H2O molecules

Can break apart whole lattice and allow ions to be surrounded by water

Question 14

Why are non-polar substances insoluble in water

Answer 14

Canr form hydrogen bonds with water

Therefore don’t release enough energy to disrupt the hydrogen bonding in water

Question 15

Why is water a liquid at RT when similar Mr molecules a gas

Answer 15

Hydrogen bonding

Question 16

How do London forces work

Answer 16

One molecule approaches another

Electric cloud repelled and displaced temporarily- set up temporary dipole

Lots of molecules together sets up fleeting temporary attractions

Question 17

When does permanent dipole occur

Answer 17

Between two polar molecules

Question 18

When does hydrogen bonding occur

Answer 18

H atom covalently bonded to a highly electronegative atom

An unshared pair of electron don a bother highly electronegative atom on another molecule