Chapter 12, Problem 21A

(a)

Interpretation Introduction

Interpretation:

The electronic configuration of the given atom and its most stable ion is to be written.

Concept introduction:

The electronic configuration is the arrangement of electrons in an atom. The atoms lose or gain electrons to acquire noble gas configuration because the ion which achievesthe nearest noble gas configuration is most stable.

Answer to Problem 21A

  $\text{C}\text{a}\text{f}\text{o}\text{r}\text{m}\text{s}\text{C}{\text{a}}^{2+}$ .

Explanation of Solution

Calciumbelongs to the 2^ndgroup. So it has a tendency to lose two electrons and form the most stable ion $\text{C}{\text{a}}^{2+}$ .

Electronic configuration of $\text{C}\text{a}$ according to Aufbau’s Principle is:

  $1{\text{s}}^{2}2{\text{s}}^{2}2{\text{p}}^{6}3{\text{s}}^{2}3{\text{p}}^{6}4{\text{s}}^2$

Therefore, Electronic configuration of $\text{C}{\text{a}}^{2+}$ :

  $1{\text{s}}^{2}2{\text{s}}^{2}2{\text{p}}^{6}3{\text{s}}^{2}3{\text{p}}^6$

It attains configuration as $\text{A}\text{r}$ .