Question

Write the trends in the valency of elements in a group.

Answer 1

Step 1:

The vertical columns of the long form of modern periodic table are called groups. There are 18 groups.

The valence electrons are the electrons present in the outermost shell of the element.

Step 2:

The elements of a group have same number of valence electrons and same valency. But the valence shells are different for different elements of the same group.

Example: Consider group 1 elements like Lithium ($\mathrm{Li}$), Sodium ($\mathrm{Na}$) and Potassium ($\mathrm{K}$).

Electronic configuration of Lithium is (2,1).

Electronic configuration of Sodium is (2,8,1).

Electronic configuration of Potassium is (2,8,8,1).

So, the valency of elements down the group remains same.