Question

what is the periodic trend in the variation of valency while going down a group? Explain your answer with reference to group 1,group 2 and group 18.

Answer 1

The valency remains same while going down the group. Since all the elements are arranged according to atomic number and chemical property.
valency of lithium and sodium is same i.e 1 they are present in group 1.
valency of magnesium and calcium is same i.e 2 they are present in group 2.

Answer 2

Answer:

Explanation:

(i) All the elements in a group have the same number

of electrons in the outermost shell. Therefore,

down the group, valency remains the same.

(ii) Valency of group 1 elements is 1 and that of group

2 elements is 2.

(iii) The valency of group 18 elements is zero because

they are noble gases with completed outermost

shell.