Question

What’s the difference between electrovalency, covalency and valency?

Answer 1

Hint: Electrovalency is the number of electrons exchanged during formation of an ion, covalency is the maximum number of electrons shared with another atom and valency is the number of electrons that an atom will gain or lose to get stable configuration.

Complete step-by-step answer:
- Electrovalency: The charge on an ion is called its electrovalency. It is the little positive or negative number written as a superscript to the right of a chemical symbol. For example, sodium has an electrovalency is +1 while bromine has an electrovalency of -1. The magnitude of the electrovalency of an atom depends upon the number of electrons exchanged in the reaction. Like in sodium $$N{a}^{+}$$, one electron has been removed and in bromine $$B{r}^{-}$$ one electron has been gained.
- Covalency: The number of bonds that can be formed by the atom of an element through sharing of electrons with other atoms in empty orbitals is called covalency. It is always a positive integer and determined by the number of vacant orbitals in an atom. For example, covalency of phosphorus is 5, that is its group number-10 as it is a p-block element. For s-block, it is the same as the group number.
- Valency: Valency is the number of electrons that an atom will either lose or gain in order to stabilize itself. It may or may not be equal to the number of valence electrons. It can be given for elements that can form ionic as well as covalent bonds. But it is a mere concept as it does not involve electronic transitions having only one value. For example, nitrogen has five valence electrons but its valency is 3.

Note: The valency may be equal to the number of valence electrons of an atom but often it is different. Covalency is totally dependent on the number of valence electrons of an atom. Whereas electrovalency totally refers to ionic forms of an atom.