Question
Question: The increasing order of the first ionization enthalpies of the elements B, P, S and F (lowest first)...
The increasing order of the first ionization enthalpies of the elements B, P, S and F (lowest first) is :
A
F < S < P < B
B
P < S < B < F
C
B < P < S < F
D
B < S < P < F
Answer
B < S < P < F
Explanation
Solution
Element : B S P F
I.E.(kJ mol–1) : 801 1000 1011 1681
In general as we move from left to right in a period, the ionization enthalpy increases with increasing atomic number. The ionization enthalpy decreases as we move down a group. P (1s2, 2s2, 3s2 3p3) has a stable half filled electronic configuration than S (1s2, 2s2, 2p6, 3s2, 3p4). For this reason, ionization enthalpy of P is greater than S.