Chemical Properties of Group 14 Elements
The reactivity of elements decreases down the group. The inert pair effect becomes increasingly effective down the group. The stability of the +4 oxidation state decreases while that of the +2 oxidation state increases on descending the group.
Sn2+ exists as simple ion and is strongly reducing.
Sn4+ is covalent.
Pb2+ is ionic, stable and more common than Pb4+.
Action of Water
C, Si and Ge are unaffected by water. Sn reacts with steam to give SnO2 and H2. Pb is unaffected by water due to the formation of protective oxide layer at the surface.
Action of Acids
C, Si and Ge are unaffected by dilute acids. Sn and Pb reacts with dilute nitric acid.
|4Sn + 10HNO3 4Sn(NO3)2 + NH4NO3 + 3H2O
|3Pb + 8HNO3 3Pb(NO3)2 + 2NO + 4H2O.
Action of Alkalis
C is not affected by alkalis.
Si reacts with alkalis forming silicates.
Sn and Pb also react with alkalis forming stannate, [Sn(OH)6]2-,and plumbate
These reactions show that Sn and Pb are amphoteric.
Action of Halogens
Graphite but not diamond is affected by F2 at higher temperatures giving (CF)n.
Si and Ge react with all halogens, forming volatile SiX4 and GeX4.
Sn and Pb are less reactive but do react giving SnX4 and PbX2.