Cation are smaller & anions larger in radii than their parent atoms because there is a loss of electrons from valence shell in the case of cation ,so decreases the shell number and in the case of anion there is addition of electrons.

When an atom has its electrons attracted to another atom it becomes a positive ion. The positive ion is smaller than the original atom. This means that with fewer electrons but the same number of positive protons, the size of the ionic radius will decrease.

Why monovalent ions (m+)are smaller than the parent atom ? 1. whereas,Radius of anion is greater than that of parent atom due to increase in no of shells and addition of electrons cause electron electron repulsion because of which size expands.

Cations are always smaller than the neutral atom and anions are always larger.

Ions aren’t the same size as the atoms they come from. Compare the sizes of sodium and chloride ions with the sizes of sodium and chlorine atoms. Positive ions are smaller than the atoms they come from. Sodium is 2,8,1; Na+ is 2,8.

Which element in each pair has the larger first ionization energy? Sodium has the larger first ionization energy and in the second pair, Phosphorus has the largest first ionization energy.

Periodic Trends — Ionization Energy

The third ionization energy is even higher than the second. Successive ionization energies increase in magnitude because the number of electrons, which cause repulsion, steadily decrease. This is not a smooth curve There is a big jump in ionization energy after the atom has lost its valence electrons.

Down in a group ionization potential decreases so, the ionization potential of sulphur is lower than the oxygen. So, sulphur has the lowest ionization potential among all four. Therefore, option (C) sulphur is correct.

sodium