Question

a. Define valency and variable valency with examples.

b. If the valency of nitrogen is 3 and of hydrogen is 1. Write down the formula for ammonia?

Answer 1

a. Valency is the combining capacity of an element. The number of elements donated or accepted by an atom of an element so as to have an electronic configuration of nearest noble gas is known as valency. Example: The valency of oxygen is 2 and carbon is 4

Sometimes, because of various conditions under which a chemical reaction takes place, the valency of the same element changes. Therefore, metals like lead, tin, copper, mercury, iron etc exhibit variable valency

b. $N{H}_3$