Question

Elements are broadly classified into metals and non-metals. State six general differences in the physical properties of metals and non-metals. State two metals and two non-metals which contradict with the general physical properties – giving reasons. State one difference in property between metalloids and noble gases.

Answer 1

Metallic elements :

1. Have lustre – i.e. shine.
2. Are malleable – i.e. can be beaten into sheets.
3. Are ductile – i.e. can be drawn into wires.
4. Are good conductors of heat and electricity.
5. have high melting and boiling points.
6. Have a high density.
7. Contain – one type of atom – monoatomic

Non-metallic Elements :

1. Do not have lustre.
2. Are non-malleable – i.e. cannot be beaten into sheets.
3. Are non-ductile – i.e. cannot be drawn into wires.
4. Are poor conductors of heat and electricity.
5. Have low melting and boiling points.
6. Have a low density.
7. Contain – monoatomic or diatomic atoms.

Two metals which contradict properties :

1. Mercury - Mercury is liquid at room temperature whereas metals are mostly solid.
2. Zinc - Zinc is Non-malleable and Non-ductile, which contradicts metal, which is malleable and ductile.

Two Non-metals are :

1. Iodine - Iodine is lustrous contradicts non-metals have no lustre.
2. Graphite - Graphite is a good conductor of electricity, whereas non–metals are poor conductors of electricity.

Difference between metalloids and noble gases:

Metalloids are chemically reactive whereas noble gases are chemically inert or inactive.