Question

Chemical compounds in which anions and cations are held together by electrostatic force of attraction are known as ionic compounds. Cations and anions are charged species which are formed by losing and gaining electron(s) respectively to attain the nearest noble gas configuration or stability. Usually metals lose their valence electrons to form cations while non-metals accept electrons and form anions. Being held by a strong electrostatic force of attraction between ions, ionic compounds have high melting and boiling points.

(i) Which of the following electronic configuration is correct for the given elements?

• A. Na: 2, 8, 2
• B. Mg: 2, 8, 1
• C. Cl: 2, 8, 7
• D. O: 2, 8, 6

Answer 1

The correct option is C Cl: 2, 8, 7

Electronic configuration for the given elements according to their atomic number is as following:
$$\begin{array}{ccc}\text{Element}& \text{Atomic no.}& \text{Electronic configuration}\\ \text{Sodium}& \text{11}& \text{2, 8, 1}\\ \text{Magnesium}& \text{12}& \text{2, 8, 2}\\ \text{Chlorine}& \text{17}& \text{2, 8, 7}\\ \text{Oxygen}& \text{8}& \text{2, 6}\end{array}$$
It is clear from the above table that electronic configuration of only chlorine is given correctly in the options.