Question

In a period, if the atomic radius of the first element is 152 pm. What is the atomic radius of the third element - more than or less than 152 pm?

Answer 1

The horizontal rows present in the periodic table are called periods.

In the periodic table total of 7 periods are present.

• In the periodic table, on moving left to right in the periodic table, the number of electrons present in the outermost shell of the element keeps on increasing in the same shell.
• The atomic radius of the element decreases along the period when moving from left to right in the periodic table.
• So, the effective nuclear force of attraction between the nucleus and the outermost shell's electron increases because the nucleus binds with the valence electron more tightly, and thus, the atomic radius keeps on decreasing.
• The force of attraction between the nucleus and valence shell electron keeps on increasing which ultimately decreases the atomic radius.

Therefore, in a period, if the atomic radius of the first element is $152\mathrm{pm}$, then the atomic radius of the third element will be less than $152\mathrm{pm}$.