Question

Explain the difference between the valence electrons and the covalency of an element?

Answer 1

Hint: You can answer this question easily because one of these terms is the number of an electron that an atom will gain or lose in order to stabilize itself while another one is related to covalent bonds. Now try to explain the difference.

Complete step by step answer:

The number of bonds an atom can form within a molecule is known as covalency. It is the maximum number of covalent bonds that an atom can form using its empty orbitals.
For example, if we have a carbon atom, the covalency of carbon is 4.
Valency is the number of electrons that will lose or gain in order to make itself stable and attain a configuration. Valency is the number of free electron/electrons in the outermost shell of an element. These electrons are called valence electrons. The greatest valency could be 4.
Valency may or may not be equal to the number of valence electrons. Whereas, covalency depends on the number of valence electrons.
Covalency is defined for elements that form covalent bonds whereas valency is used for covalent and ionic bonds.

We can interrelate both of them by this example of carbon that would explain to us the basic difference between these terms,
When the valency of an element is 4 it can neither lose nor accept 4 electrons to form an ionic bond because it would be difficult for nucleus with six protons to hold on to ten electrons, which is four extra electrons. (take in case of carbon with valency 4).
Also, it would require a large amount of energy to remove four electrons leaving behind a carbon cation with six protons in its nucleus holding on to just two electrons.
Carbon overcomes this problem by sharing its valence electrons with atoms of other elements. Not just carbon but many other elements form molecules by sharing the outer shell electron in this manner such bonds which are formed by sharing of an electron pair between two atoms are known as a covalent bond.

Therefore, we explained the difference between the valence electrons and the covalency of an element.

Note: You should be aware of these points too -
Valency usually provides all the required amount of electrons to complete all the free orbitals; on the other hand, covalency is determined by the number of free electrons that exist in an atom.
Valency could either have a positive value or a negative value; conversely, covalency is generally always a positive value.