Classification

The relative extent to which the various orbitals penetrate the electron clouds of other orbitals is . Electron will experience the greatest effective nuclear charge when in -orbital, then a -orbital and so on. Ionisation energy increases with an increase in penetration power and thus, the order of screening effect is .

Generally, acidic nature of oxides increases along a period from left to right and decreases along a group from up to down.
Since and all belong to group and arranged in the following manner :

is the most and is the least acidic.

On moving along a period, the tendency to lose electrons decreases and thus, the metallic character decreases. Since, the oxides of non-metals are acidic. Thus, it can be said, along a period from left to right basic character decreases while on moving downward, basic character increases due to increase in metallic character.

Ionisation energy is the energy required to remove an electron from outer shell of an atom. Since, on moving from left to right in a period, size decreases, thus, larger amount of energy is required to remove an electron, ie, ionisation energy increases.
Although the size of atom is smaller as compared to but the ionisation energy of is higher. This is because in case of , the electron is to be removed from half-filled orbital. Thus, the order of ionisation energy is

In the Periodic Table, the minimum ionisation energy is found at alkali metals. Hence sodium (electronic configuration has the lowest ionisation energy.
Note : - Ionisation energy is the amount of energy required to remove an electron from the outermost shell an isolated atom.

atom has highest electron affinity ( has highest) in the periodic table
Among the given options
has highest electron gain affinity