Question

Sort the given elements in the descending order of their valency.

• A. Neon
• B. Magnesium
• C. Hydrogen
• D. Boron

Answer 1

Valency is the combining capacity of an element. It is determined by the number of valence electrons.

If number of valence electrons are four or less than four, then
Valency = number of valence electrons

If number of valence electrons are greater than four, then
Valency = 8 - number of valence electrons

$\begin{array}{cccc}\text{Element}& \text{Atomic number}& \text{Electronic configuration}& \text{Valency}\\ \text{Hydrogen}& 1& \left(1\right)& 1\\ \text{Boron}& 5& (2,3)& 3\\ \text{Neon}& 10& (2,8)& 0\\ \text{Magnesium}& 12& (2,8,2)& 2\end{array}$

Hence, the descending order of the given elements depending on their valency is:
Boron > Magnesium > Hydrogen > Neon.