# The increasing order of the first ionisation enthalpies of the elements B, P, S and F (lowest first) is Option 1) $F Option 2) $\; P Option 3) $\; B Option 4) $\; B

As we learnt in

Ionization enthalpy -

It is defined as the minimum amount of energy required to remove the outer most shell electron from an isolated gaseous atom (X) to form the gaseous ion.

- wherein

$X_{(g)}\rightarrow X^{+}_{(g)}$  $+e^{-}$

Along a period from left to right, I.E increases with increasing atomic number, and ionization enthalpy decreases down the group. But P has a half filled stable configuration as compared to S and because of that ionization enthalpy of P is higher than S.

Option 1)

$F

This option is incorrect.

Option 2)

$\; P

This option is incorrect.

Option 3)

$\; B

This option is incorrect.

Option 4)

$\; B

This option is correct.

### Preparation Products

##### JEE Main Rank Booster 2021

This course will help student to be better prepared and study in the right direction for JEE Main..

₹ 13999/- ₹ 9999/-
##### Knockout JEE Main April 2021 (Subscription)

An exhaustive E-learning program for the complete preparation of JEE Main..

₹ 4999/-
##### Knockout JEE Main April 2021

An exhaustive E-learning program for the complete preparation of JEE Main..

₹ 22999/- ₹ 14999/-
##### Knockout JEE Main April 2022

An exhaustive E-learning program for the complete preparation of JEE Main..

₹ 34999/- ₹ 24999/-