Question

Match the elements of List I to appropriate element of List II.

Answer 1

As we move from left to right in a period atomic size decreases because of increase in nuclear charge but taken in consideration that noble gases have Van der Waal's radius largest radius in the period. Hence surely the last element in the second period will have $1s^{2}2s^{1}2p^6$ configuration. Hence it has 10 electrons i.e. neon. Therefore A matches to 4.

As we move from top to bottom in a group atomic size increases because of the addition of new shell (with some exceptions e.g. radius of $Al>Ga$). Hence in the 13th group, the first element is the smallest element that is boron. Hence B matches to 1.

Fluorine has only one unpaired electron and if it gets one more electron it gets octet configuration which is very stable hence it has large tendency to accept an electron. In the halogen group, fluorine is the smallest element hence it will have more tendency to accept electron than remaining. Hence fluorine has the highest electron affinity that is it has highest non-metallic nature. Hence C matches to 2.

Already discussed the element in a period which has the smallest size will be the last but one element in a period, the Noble gases have Van der Waal's radius. That's the reason why they are bigger than halogens in size. Hence bromine is smaller in size in the fourth period. Hence D matches to 3.