Question

explain why the first ionization energy of Na is lower than that of Mg while the second ionization energy of Na is higher than that of Mg?
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Answer 1

Answer:

Hence, in case of sodium, the second electron has to be removed from the stable noble gas configuration. Consequently, removal of a second electron from sodium requires more energy in comparison to that required in magnesium. Therefore, the second ionization enthalpy of sodium is higher than that of magnesium.

The electronic configurations are as follows:

Na - [ Ne ] 3s

Mg - [ Ne ] 3s

Sodium has one valence electron in 3s

and by losing this electron it attains stable configuration. Therefore the 1st ionization energy of Na is less than Mg. After removing an electron the Na attains noble gas configuration whereas Mg has one electron left. To remove an electron from a noble gas configuration high energy is required.

Explanation:

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