(1) Non-metallic nature : The non-metallic nature decreases along the group.
| C |
Si |
Ge |
Sn |
Pb |
| Non-metals |
Non-metals |
metalloid |
metal |
metal |
(2) Abundance : Carbon and silicon are most abundant elements in earth’s crust whereas germanium occurs only as traces. Tin and lead also occur in small amounts. Only carbon occurs in free state as coal, diamond and graphite and in combined state as carbonates, CO2 petroleum and natural gas Silicon is the second most abundant element after oxygen in earth’s crust in form of silicates and silica. Germanium found in traces in coal and in certain deposits. It important constituent for making conductors and transistors The important ore of tin is tin stone (SnO2) or cassiterite. Lead is found is form of galena (PbS) anglesite (PbSO4) and cerussite (PbCO3) The abundance ratio in earth’s crust is given below,
(3) Density : The density of these elements increases down the group as reported below
| Element |
C |
Si |
Ge |
Sn |
Pb |
| Density (g/ml) |
3.51 (for diamond) |
2.34 |
5.32 |
7.26 |
11.34 |
| |
2 (for graphite) |
|
|
|
|
(4) Melting point and boiling points
(i) The melting point and boiling point of this group members decrease down the group.
| Element |
C |
Si |
Ge |
Sn |
Pb |
| m.pt(K) |
4373 |
1693 |
1218 |
505 |
600 |
| b.pt.(K) |
--- |
3550 |
3123 |
2896 |
2024 |
(ii) The melting point and boiling point of group 14 elements are however, higher than their corresponding group 13 elements. This is due to the formation of four covalent bonds on account of four electrons in their valence shells which results in strong binding forces in between their atoms in solid as well as in liquid state
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