Question

Explain how the sodium is monovalent.

Answer 1

An atom is monovalent if there is only one electron present in its valence shell. Valence shell is defined as it is the outermost shell of every element. Atoms of every element have different electronic configurations based on the atomic number of each element so they also have different valence electrons present in its valence shell.

Complete step by step answer
To explain the monovalent of an atom or an element. First, we have to know its electronic configuration of that atom. In our question we have to explain sodium is monovalent.
Since, the electronic configuration of sodium is $1{s^2}2{s^2}2{p^6}3{s^1}$ . It has only one electron present in its last shell which means it has a $1$ valence electron. In order to attain the stability it acquired the nearest noble gas configuration. Sodium prefers to lose $1$ electron from its valence shell. Therefore, we can say that sodium has a valency of one that’s why it is a monovalent atom.

Additional Information
Sodium is a chemical element with the symbol $Na$ and atomic number is $11$ . It is a soft (can be cut with a knife), silvery-white and highly reactive metal. Sodium is present in group $1$ in the periodic table also known as alkali metal. It does not occur free metal in nature due to its high reactive nature. Sodium is the sixth most abundant element in the Earth’s crust and exists in numerous minerals such as sodalite and rock salt.

Note:
Valency is defined as the combining capacity of an atom as its valency. The number of bonds that an atom can form as a part of a compound is expressed by the valency of the element. For example, nitrogen forms a number of compounds with hydrogen such as $N{H_3},{N_2}{H_4}$ in which nitrogen atoms have valencies of $3$ and $2$ respectively. Thus, this concept of valency as a mere number was not clear. Therefore, later on valency was defined as the number of chemical bonds formed by an atom in a molecule.