Question

Given below are the atomic radii of three elements X, Y and Z of the periodic table, each

having n electrons in the outermost shell of their atoms:

Element X Y Z

Atomic radii 133 pm 157 pm 202 pm

Answer the following:

(a) Do these elements X, Y and Z belong to same group or to the same period?

(b) Which element will be least metallic?​

Answer 1

a. They belong to the same group.

b. Element X with an atomic radii of 133 pm will be the least metallic in nature.

I hope this helps.

Answer 2

Atomic radius increases in going top to bottom in a group and decreases in going from left to right in a period.

(a) From the three elements, we can clearly see that X, Y, Z are in increasing order and atomic radius increases down the group. So, element X, Y and Z belongs to same group.

(b) Element X will be least metallic because smaller atoms have strong electrostatic force due to which it makes the element really difficult to loose electrons.