Question

Sodium forms $N{{a}^{+}}$ ion but it doesn’t form $N{{a}^{+}}$ because of
(A) Very low value of first and second I.E
(B) Very high value of first and second I.E
(C) High value of first I.E and low value of second I.E
(D) Low value of first I.E and high value of second I.E

Answer 1

Hint: The ionization energy is defined as the energy required to remove an electron from the outermost shell of a nucleus. We will have to find the configuration of the sodium atom and decide whether it is being formed with low ionization or high ionization energy.

Complete step by step answer:
In the previous classes of basic chemistry, we have dealt with the topics of inorganic chemistry that tell about atoms and the trends in the periodic table like trends in ionization energy across groups and periods, trends in electron affinity, and so on.
Let us see the reason for the formation of monovalent sodium ions and not divalent ions.
- Sodium has an atomic number of 11 and mass number 23 with the symbol $Na$ and has the electronic configuration of $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{1}}$.
- The electronic configuration of any elements coming after helium can be written in the form of shorthand notation where the valence electron is written outside the brackets preceded by the respective noble gas configuration.
- Therefore, the shorthand notation of sodium can be written as $[Ne]3{{s}^{1}}$
- Now since the valence electron in the sodium is 1, thus the notation is $[Ne]3{{s}^{1}}$
- Here we remove an electron then the configuration will be $[Ne]$ so one electron can be removed easily
- After removing an electron the configuration is $[Ne]$ so it is a noble gas configuration.
- It is a highly stable configuration so a lot of energy has to be given to remove the electron
- Hence it has a low value for the first ionization energy and a high for the second.
So, the correct answer is “Option D”.

Note: The ionization depends on the relative distance of the electron to the nucleus. Also, more is the separation less is the energy, and the energy required will be more for the inner electrons because they are strongly attracted to the nucleus.