Question

An element $'X'$ has valency of $H$ . Write its formula for Nitrate .

Answer 1

The number of electrons lost or gained or shared by an atom to become stable or to achieve an octet in the outermost shell is known as the valency of that element .

Complete step by step answer:
The electrons present in the outermost shell of an atom are known as the valence electrons . They govern the chemical properties of atoms . The atoms of elements having completely filled outermost shell means which has eight electrons show little chemical activity , that is , they are highly stable . Such elements are called inert elements . It means n, their valency is zero .
The tendency to react with atoms of the same or different elements to form molecules is an attempt to attain a fully - filled outermost shell . It means , atoms react with other atoms in order to attain a fully filled outermost shell . An outermost shell ,which has eight electrons is called an octet . Atoms react to achieve their octet . This is done by sharing , gaining or the loss of electrons . The number of electrons lost or gained or shared by an atom is the valency of that element .
In the question , it is given that the element $'X'$ has a valency of $H$ , and $H$ has a valency of $+ 1$ , hence valency of $'X'$ is $+ 1$ .
Also the formula of nitrate is $N{O_3}^ -$ , so its valency is $- 1$ .
Hence the formula of the compound should be $XN{O_3}$ .

Note: The valency of an element is related to the number of electrons present in the outer shell or valence shell.
For elements having one, two, three or four electrons in the valence shell, the valency is equal to the number of valence electrons. Whereas for elements having five, six, seven or eight electrons in the valence shell, the valency is equal to $\left( {8 - number{\text{ }}of{\text{ }}valence{\text{ }}electrons} \right)$ .