Section 4

Question 1

Shapes of molecules

What does the dotted line show

Answer 1

Bond pointing away

Question 2

Shapes of molecules

What does block line show

Answer 2

Bond facing towards you

Question 3

Shapes of molecules

2 bonding pairs

Answer 3

Linear

180

Question 4

Shapes of molecules

3 bonding pairs

Answer 4

Trigonal planar

120

Question 5

Shapes of molecules

4 bonding pairs

Answer 5

109.5

Tetrahedral

Question 6

Shapes of molecules

3 bonding pair and 1 lone pair

Answer 6

Trigonal pyramidal

107

Question 7

Shapes of molecules

5 bonding pairs

Answer 7

120 and 90

Question 8

Shapes of molecules

6 bonding pairs

Answer 8

90

Octahedral

Question 9

Why do shapes become squished when there’s a lone pair?

Answer 9

Because the lone pair/bonding pair repulsion is stronger than the bonding pair/bonding pair repulsion

Question 10

Electronic structure

s electrons

Answer 10

2

Question 11

Electronic structure

p electrons

Answer 11

6

Question 12

Electronic structure

d electrons

Answer 12

10

Question 13

Electronic structure

f electrons

Answer 13

14

Question 14

Electronic structure

1st shell

Answer 14

2

Question 15

Electronic structure

2nd shell

Answer 15

8

Question 16

Electronic structure

3rd shell

Answer 16

18

Question 17

Electronic structure

4th shell

Answer 17

32

Question 18

Electronic structure

p orbital shape

Answer 18

3 p-orbitals at right angles to each other

Question 19

Electronic structure

Why does 4s fill up before 3d?

Answer 19

It has a lower energy level even though it has a higher principal quantum number

Question 20

Electronic structure

Electron configuration up to 3d

Answer 20

1s2 2s2 2p6 3s2 3p6 4s2 3d10

Question 21

Ionic bonding

Answer 21

Attraction between oppositely charged ions

Question 22

Ionic bonding

Electrical conductivity

Answer 22

Conduct when molten or dissolved but not when solid because ions are free to move in liquid but are fixed in place by ionic bonds in solid

Question 23

Ionic bonding

Melting and boiling points

Answer 23

High mp and bp because a lot of energy is needed to overcome these forces

Question 24

Ionic bonding

Solubility

Answer 24

Dissolve in water

Water molecules are polar so have small charges which pull ions away from lattice

Question 25

Covalent bonding

Answer 25

Electrostatic attraction between a shared pair of electrons

Question 26

Covalent bonding | Dative covalent bonding

Answer 26

One of the atoms provides both the sharing electrons

Question 27

Covalent bonding - special cases | 6 electrons in outer shell

Answer 27

boron trifluoride

Question 28

Covalent bonding - special cases | 12 electrons in outer shell

Answer 28

sulphur hexafluoride

Question 29

Covalent bonding | How to find out strength

Answer 29

Average bond enthalpy | Energy required to break covalent bond

Question 30

Polarisation | Electronegativity

Answer 30

The ability for an atom to attract electrons in a covalent bond

Question 31

Polarisation | Non-polar

Answer 31

No overall dipole

Question 32

Polarisation | Polar

Answer 32

Has an overall dipole

Question 33

Intermolecular forces | Induced - larger molecules

Answer 33

Have a larger electron cloud meaning stronger induced dipole dipole

Question 34

Intermolecular forces | Permanent

Answer 34

Delta charges cause weak electrostatic forces of attraction between molecules

Question 35

Intermolecular forces | Hydrogen - ice less dense

Answer 35

Ice has more hydrogen bonds are they're relatively long so the molecules will be further apart making it less dense

Question 36

Simple covalent compounds

Answer 36

Have weak forces between molecules which affects their physical properties

Question 37

Simple covalent compounds | Electrical conductivity

Answer 37

The covalent molecules are uncharged so cannot conduct electricity

Question 38

Simple covalent compounds | Melting and boiling points

Answer 38

Normally low due to weak intermolecular forces

Question 39

Simple covalent compounds | Solubility

Answer 39

If doesn't have hydrogen bonds, won't be very soluble

Question 40

Simple covalent compounds | Trends in mp and bp

Answer 40

As you go down group, less polar so weaker permanent dipole-dipole interactions More electrons which increases induced dipole-dipole interactions