Question

Atomic numbers of nitrogen, oxygen and fluorine are 7, 8 and 9 respectively. Write the electronic configuration of each element and answer the following question:

What is the valency of each one of N, O and F?

Answer 1

Step-1: Introduction

The elements in periodic table are placed in periods and groups. Periods are horizontal rows that has increasing atomic numbers. Groups are vertical columns. There are 7 periods and 18 groups in periodic table.

Step-2: Electronic configuration

Atomic numbers of Nitrogen ($\mathrm{N}$), Oxygen ($\mathrm{O}$), and Fluorine ($\mathrm{F}$) are 7, 8, and 9 respectively.

Electronic configuration of Nitrogen = (2, 5).

Electronic configuration of Oxygen = (2, 6).

Electronic configuration of Fluorine = (2, 7).

Step-3: Valency of elements

The metal valency is calculated by the valence electron count in the valence shell but in non-metals, 8 minus the valence electron count gives the valency.

The valency of the element rises from left to right during a certain period and drops down. It rises till the number 4 later falls and reaches 0 in the case of noble gases.

Since Nitrogen, Oxygen, and Fluorine are non-metals, valency can be calculated by the following:

$$\begin{gathered} \mathrm{Valency}\mathrm{of}\mathrm{Nitrogen}=8-5=3 \\ \mathrm{Valency}\mathrm{of}\mathrm{Oxygen}=8-6=2 \\ \mathrm{Valency}\mathrm{of}\mathrm{Fluorine}=8-7=1 \end{gathered}$$

Therefore, the valency of Nitrogen, Oxygen, and Fluorine are 3, 2, and 1 respectively.