Question

The first ionization potentials $\left(eV\right)$ of $Be$ and $B$ respectively are

• A. $8.29eV,8.29eV$
• B. $9.32eV,9.32eV$
• C. $8.29eV,9.32eV$
• D. $9.32eV,8.29eV$

Answer 1

Answer: (D)

$9.32eV,8.29eV$

First ionisation potential of $$Be$$ is greater than boron due to stable cofiguration.

${}_{4}Be=1s^2,2s^2$

${}_{5}B=1s^2,2s^{2}2p^1$

Order of attraction of electrons towards nucleus is $2s>2p,$ Therefore more amount of energy is required to remove the electron from 2s orbital in comparission to 2p orbital.Therefore ionisation potential of Be is $9.32eV$ and B is $8.29eV$.