AP EAMCET2011ChemistryClassification of Elements and Periodicity in Properties
Which one of the following is correct order of second ionisation potential of Na , Ne , Mg and Al ?
Options
- AAl < Na < Mg < Ne
- BNe < Al < Na < Mg
- CMg < Al < Ne < Na
- DNa < Mg < Ne < Al
Correct answer
C. Mg < Al < Ne < Na
Step-by-step solution
The electronic configuration of Na , Ne , Mg and Al after the removal of an electron is as aligned & Na ⁺: 1 s^2, 2 s^2, 2 p^6 & Ne ⁺: 1 s^2, 2 s^2, 2 p^5 & Mg ⁺: 1 s^2, 2 s^2, 2 p^6, 3 s^1 & Al ⁺: 1 s^2, 2 s^2, 2 p^6, 3 s^2 aligned The ionisation energy decreases as the size of the atom/ion increases. Further ionisation energy increases with increase in nuclear charge. Since, Na ⁺ gives a stable electronic configuration hence its IE ₂ is highest among the given species and therefore the correct order of their IE ₂