Question

how do atomic radius vary in a period and in a group? how do you explain the variations?​

Answer 1

Answer:

In general, the atomic radius decreases as we move from left to right in a period with an increase in nuclear charge of the element. The atomic radius increases when we go down a group because of the addition of extra shell.

Explanation:

Answer 2

Answer:

In a period, from left to right, with increase in the atomic number, the atomic radius decreases due to increase in the nuclear charge which increases the attraction of the nucleus for the valence electrons.

In a group, on moving from top to bottom, the ionic radius increases as a new energy level is added at each succeeding element but the number of valence electrons remains same.

Hope this helps you