GENERAL KNOWLEDGE

Detailed explanation-1: -Down a group, the number of energy levels (n) increases, and so does the distance between the nucleus and the outermost orbital. The increased distance and the increased shielding weaken the nuclear attraction, and so an atom can’t attract electrons as strongly.

Detailed explanation-2: -The number of electron shells increases by 1 as we go down a group. You can see this from the electron configuration [H]=1s1 [ H ] = 1 s 1 and [Li]=1s22s1 [ L i ] = 1 s 2 2 s 1 . The number of protons and electrons for the neutral atom of the elements increases as we go down the group.

Detailed explanation-3: -As we go across a period from left to right, we add a proton to the nucleus and an electron to the valence shell with each successive element. As we go down the elements in a group, the number of electrons in the valence shell remains constant, but the principal quantum number increases by one each time.

Detailed explanation-4: -On the periodic table, atomic radius generally decreases as you move from left to right across a period (due to increasing nuclear charge) and increases as you move down a group (due to the increasing number of electron shells).