Question

If successive ionization energies of an element are 7.9 ev, 13.2 ev and 247.8 ev respectively, the element is expected to be?

Answer 1

The expected element:

• The ionization energy of the expected element is given as$;7.9\mathrm{ev},13.2\mathrm{ev},\mathrm{and}247.8\mathrm{ev}$ respectively.
• The ion has invested a lot of energy (247.8 eV) to release the third electron after releasing two electrons from its valence shell.
• This indicates that the ion has entered the noble gas configuration after the release of two electrons (since noble gases have high ionization values).
• Therefore, the valence of the element must be 2.
• Any group 2 elements having the valency 2 can be expected to be the given element.
• The valency of Calcium (Ca) is also given as 2, so we can expect, the element will be Calcium.

Hence, the element given having the respective ionisation energy can be expected to be Calcium (Ca).