Question

Write down the difference in the
a)Physical properties of metals and non-metals
b)Chemical properties of metals and non-metals
c)Calcination and Roasting

Answer 1

(a) Physical properties Metals :-

1. Metals possess a lutsre
2. Metals are generally hard
3. They are malleable
4. They are ductile
5. They are solids at room temperature except mercury
6. They are good conductors of heat and electricity

Physical properties Non- metals :-

1. Non –metals do not possess luster
2. They are brittle if solid
3. They are not malleable
4. They are not ductile
5. They can be solids, liquids or gases at room temperature
6. They are poor conductors of heat and electricity.

(b)Chemical Properties Metal :-

Usually have 1-3 electrons in their outer shell.
Lose their valence electrons easily.
Form oxides that are basic.
Are good reducing agents.
Have lower electronegativities.

Chemical Properties Non metal :-

Usually have 4-8 electrons in their outer shell.
Gain or share valence electrons easily.
Form oxides that are acidic.
Are good oxidizing agents.
Have higher electronegativities.

(c) The differences between roasting and calcination are given below:

Roasting	Calcination
Heating in the presence of air	Heating in the absence of air
Sulphide ores are roasted	Carbonate ores are calcined
Sulphur dioxide is released	Carbon dioxide is released
reaction showing roasting process heat 2ZnS + 3O2 --------> 2ZnO + 2SO2↑	reaction showing calcination process heat CaCO3---------> CaO +CO2↑
Not used for dehydrating an ore	Can be used to drive out moisture from an ore

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