Question

An element ${}^{\prime }{X}^{\prime }$ has valency of ${}^{\prime }{H}^{\prime }$. Write its formula for Nitrate.

Answer 1

Hint: In chemistry, valency of any element is fundamental things which we have to know for the formation of any compounds. We can solve this problem with the concept of valency. Valency is the concept by which we can write formulas of compounds and salts. It is the capacity by which atoms or molecules combine to each other.

Complete step by step answer:
In more elaborating form, valency is the estimation of the combining capacity of an atom due to which it reacts and combines with atoms of other elements. We know that electrons are present in the shells such as K, L, M,… etc. The electrons present in the outer shell are called valence electrons, they also contribute to the valency of elements and participate in the chemical reaction.
If the outermost shell is completely filled with electrons, it does not react like noble gases. All the elements want to gain the electronic configuration like noble gas and attain the complete octet. Hence, Valency is the total number of electrons lost, gained and shared by the elements to complete its octet.
In the given question, An element ${}^{\prime }{X}^{\prime }$ has valency of ${}^{\prime }{H}^{\prime }$ means it also have one electron in its outermost shell therefore it have $+1$ valency like hydrogen and work like cation after removal of one electron while nitrate is an anion and its valency is $-1$. Thus, the formula we get is $XN{O}_3$.

Note: Now, we can say that valency helps us to find the chemical formula. Students are confused between oxidation number and the valency often and make mistakes in the question. Oxidation number is only the charge at the atom which it carries after the removal or gain of electrons. While valency is the combining capacity.