Answer: Option (a) is the correct answer.
Explanation:
When we move from left to right in a periodic table then size of atom decreases due to which there will be decrease in atomic radius of the atom.
Whereas effective nuclear charge is the charge due to which the nucleus is able to attract the valence electrons towards itself.
On the other hand, ionization energy is the energy needed to remove an electron from a gaseous atom or ion.
The electrons present under the valence shell are known as core electrons.
Hence, we can conclude that out of the given options atomic radii decrease from left to right across a row in the periodic table.
