a.

Nitrogen and carbondioxide

b.

The rare gases

c.

Nitrogen and oxygen

d.

Nitrogen and the rare gases

a.

Ethene

b.

Propane

c.

Methane

d.

Butane

a.

Alkalis

b.

Acids

c.

Bases

d.

Salts

a.

Covalent compounds would readily ionize in solution

b.

Covalent compounds consist of ions

c.

Hydrogen bond is formed between a metal and a non-metal

d.

Ionic compounds in solution would conduct electriity