Question

An element has Z = 7. What is the valency of the element ? Also name the element.

Answer 1

We know that protons are present in the nucleus of an atom. It is the number of protons of an atom that determines its atomic number. It is denoted by ‘Z’. Here,
Atomic number = 7
Number of electrons = 7
Electronic configuration is

$\begin{array}{cc}\underset{2}{\mathrm{K}}& \underset{5}{\mathrm{L}}\end{array}$

There are 5 electrons in the outermost orbit. So, in order to complete its octet the atom will have to gain 3 electrons. Therefore, the valency of the atom is 3.
Given element is nitrogen.