arrange the following in dexresing electron gain enthalpy(negative)
b, c, n, o
Decreasing order of electron gain enthalpy: (Oxygen has most negative electron gain enthalpy)
O > C > B > N
​Variation of electron gain enthalpy along period: On moving across a period, the size of the atom decreases and nuclear charge increases. Both these factors result into greater attraction for the incoming electron, therefore, electron gain enthalpy, in general becomes more negative in a period from left to right.
Exception-
The electron gain enthalpy of nitrogen is nearly zero. This is because nitrogen has half filled p-orbital, which is very stable so it do not tend to gain electron.
O > C > B > N
​Variation of electron gain enthalpy along period: On moving across a period, the size of the atom decreases and nuclear charge increases. Both these factors result into greater attraction for the incoming electron, therefore, electron gain enthalpy, in general becomes more negative in a period from left to right.
Exception-
The electron gain enthalpy of nitrogen is nearly zero. This is because nitrogen has half filled p-orbital, which is very stable so it do not tend to gain electron.