Section BQn 1 (have a metal)

(all non-metals)

ionic

(covalent)

Grp O

Qn 2ai

2.5

1

Qn says draw only the outer electrons.Otherwise, you should show all electrons.

Non-metal

Non-metal

Qn 2aii

The intermolecular forces between the molecules are weak. They can be overcome easily with a small amount of energy.

Qn 2b

Each covalent bond is formed by sharing 2 electrons. With a total of 5 covalent bonds formed between P and O, 10 electrons are shared in total.

Qn 3a

(i) Beryllium chloride

Be Cl

2 1

BeCl2

Qn 3a

(ii) Silicon tetrachloride

SiCl4

Qn 3b

They have a completely filled outermost shell.

Qn 3ci

Each lithium atom transfer 1 electron to a chlorine atom, forming ionic bonds.

Li: 2.1 (metal) Cl: 2.8.7 (non-metal)

Qn 3cii

Each chlorine and fluorine atom share a pair of electrons, forming a single covalent bond.

Cl: 2.8.7 (non-metal) F: 2.7 (non-metal)

You can always sketch it out if to check the bonding.

Qn 3d

LiCl will have a high boiling point because it requires a large amount of energy to overcome the strong electrostatic attraction between the ions.

ClF will have a low boiling point because the intermolecular forces between the molecules are weak. They can be overcome easily with a small amount of energy.

Qn 4Look for properties of ionic substance

Look for properties of covalent substance

Only ionic substance can conduct when dissolvedin water

Section C, Qn 1a

This is due to its high melting point. A large amount of energy is needed to overcome the strong electrostatic attraction between the ions.

Qn 1b

The bulb will light up. When sodium chloride is dissolved in water, its ions can move freely to carry the charges around to conduct electricity.

C: 2.4O: 2.6

Qn 2a

Qn 2bi

There are no free moving ions or electrons present.

Qn 2bii

This is due to its low boiling point. The intermolecular forces between the molecules are weak. They can be overcome easily with a small amount of energy.

Qn 2c

(i) sodium + oxygen

Na O

1 2

Na2O Name: sodium oxide

(ii) silicon + oxygen

Si O

4 2

Si2O4SiO2 Name: silicon dioxide

(iii) calcium + oxygen

Ca O

2 2

CaO Name: calcium oxide

Qn 3

Soluble only in water

Conduct only when molten or dissolved in water

metal non-metal

(ionic)

Qn 3

No.

(It will has high boiling point since it is an ionic compound)(Only covalent substance will evaporate easily)