Question

The formula of ion formed by an element A is $A^{+2}$. The element A can probably belong to which of the following groups?

• A. IIIA
• B. VIIA
• C. IIA
• D. IA

Answer 1

The correct option is C

IIA

Explanation for Correct option:

C) Element A belongs to IIA group as it contains 2 valence electrons in its outermost shell and on losing the 2 electrons it becomes $A^{+2}$ to attain nearest inert gas configuration.

$A-2e^{-}\to A^{2+}$

Explanation for Incorrect options:

A)IIIA group element has 3 electrons in the valence shell and on losing 3 electrons, it becomes $A^{3+}$to attain nearest inert gas configuration.

B)VIIA group element has 7 electrons in the valence shell and they gain 1 electron to attain stability and becomes $A^{-}$ to attain nearest inert gas configuration.

D)IA group element has 1 electron in the valence shell and on losing 1 electron, it becomes $A^{+}$to attain nearest inert gas configuration.

Hence,C) is the correct option- the element A belongs to IIA group.