Question

The incorrect statement among the following is :

• A. the first ionisation potential of $Al$ is less than the first ionization potential of $Mg$
• B. the second ionisation potential of $Mg$ is greater than the second ionisation potential of $Na$
• C. the first ionisation potential of $Na$ is less than the first ionisation potential of $Mg$
• D. the third ionisation potential of $Mg$ is greater than the third ionisation potential of $Al$

Answer 1

The correct option is B the second ionisation potential of $Mg$ is greater than the second ionisation potential of $Na$

The second ionisation potential of $Mg$ is lesser than the second ionisation potential of $Na$.

The removal of second electron from $Mg$ takes place from $3s$-orbital whereas the removal of second electron from $Na$ takes place from $2p$-orbital.

More closer are shells to the nucleus, difficult is removal of electron.

Therefore, the correct option is B.