Question

The incorrect statement among the following is :

• A. the first ionisation potential of $Al$ is less than the first ionisation 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 of potential of $Mg$ is greatest

Answer 1

Answer: (B)

the second ionisation potential of $Mg$ is greater than the second ionisation potential of $Na$

After removal of an electron sodium acquires stable noble gas configuration. It is difficult to remove electron from stable noble gas configuration species. Therefore, second ionization potential of Mg is less than that of Na.