Answer:
a. True
Explanation:
The atomic radius is taken as the half of the inter nuclear distance between two atoms that are covalently bonded.
Across a period, the atomic radii usually decrease progressively because the nuclear charge(number of protons in the nucleus) increases without the increase in the number of electronic shell. Therefore, the electrons are pulled more to the nucleus.
Down a group, the effect of the nuclear pull is reduced because the number of electron shell increases and the nuclear charge is being compensated for.
