The increasing order of the first ionisation enthalpies of the elements B, P, S and F

• Periodic Properties

The increasing order of the first ionisation enthalpies of the elements B, P, S and F (lowest first) is

1. B < P < S < F
2. F < S < P < B
3. P < S < B < F
4. B < S < P < F

Answer

In general as we move from left to right in a period, the ionisation enthalpy increases with increasing atomic number. The ionisation enthalpy decreases as we move down a group. P (1s² 2s² 2p⁶ 3s² 3p³) has a stable half-filled electronic configuration than S (1s² 2s² 2p⁶ 3s² 3p⁴). For this reason, ionization enthalpy of P is higher than S.

The correct option is D.