Question

Define valency in terms of the combining capacity of an element

Answer 1

Valancy of an element is the number of electrons it needs to gain or lose too have a octet configuration

Answer 2

the combining capacity of an atom is called its valency.

For example lets take oxygen (electrons =8)

Electronic configuration is 2,6

But K=2 and L=8

Here in second orbit the electrons should be 8 but in oxygen these are only 6.

So to complete this shell oxygen will take 2 electrons from another atom and combine with it. Therefore, the combing capacity of oxygen is 2 .