Question

Of the elements given, which has the lowest ionization energy?
A. N
B. P
C. S
D. Cl

Answer 1

Hint: Ionization energy depends mainly upon the atomic radius of an atom and the elements full stop it also depends upon the stability of the electronic configuration.

Complete answer:
Ionization energy in chemistry refers to the smallest amount of the conserved quantity or energy which is needed to take out the outermost electron (the most less tightly or loosely bound electron) or the valence electron from the isolated gaseous molecule or atom.
Ionization energy simply means to remove the electron from the outermost shell of a gaseous isolated atom. The atoms lose electrons when they are in their ground state of energy and not in the excited state.
The withdrawal of electrons from valence shells is an endothermic process in which energy is consumed. The ionization energy of the electrons depends upon their vicinity from the nucleus. The electrons of the outermost shell of the atom are closer to the nucleus the more the amount of ionization energy needed to withdraw them. Also, if the orbitals are in a state of half filled or fully filled stability the more ionization energy is needed to withdraw the electrons from them.
Among all the above-mentioned elements nitrogen and phosphorus belongs to group 15, sulphur belongs to group 16, and chlorine belongs to group 17.
Down the group atomic size tends to increase so the size of Phosphorus is greater than nitrogen and also it will have less ionization energy than nitrogen.
Now as we move along the period the size of atomic radius decreases so the size of phosphorus will be greatest. It should according to this analysis have the lowest ionization energy. But sulphur has lowest ionization energy because it can easily attain half-filled stability by losing one electron and the buzz is lowest ionization energy among all.

The correct answer is (C).

Note: Electron Affinity-It refers to the amount of energy lost when an electron is added to a gaseous isolated atom. It is equal to the ionization energy.