Q. 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 potential of Mg is greater than that of Al
Explanation
(b)
IE (II) of Na is higher than that of Mg because in case of Na, the second $e^{-}$ has to be removed from the noble gas core while in case of Mg removal of second $e^{-}$ gives a noble gas core
Mg has high first ionisation potential than Na because of its stable $ns^{2}$ configuration
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.