Question

carbon has a valency of plus2 and plus 4 according to a chart of mine, should it not be plus 4 and minus 4.please explain clearly.the table is attached below.

Answer 1

Valency is the combining capacity of the element. It cannot be negative.

Valency of carbon is 4 where it can exhibits different oxidation states from -4 to +4

For example in CO2 oxidation state of carbon is +4 whereas in CH4 oxidation state of carbon is -4.

Carbon can either gain or lose 4 electrons to gain inert gas configuration