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What is Electronic configuration?

Electronic configuration of an atom is the arrangement of its electrons in the shells.

The formula for the maximum number of electrons in one shell is given by 𝟐𝒏^𝟐, where ‘n’ is the

shell number.

As per the electron distribution formula, the innermost shell or the first shell in an atom can accommodate a maximum of 2 electrons. And as per the first rule of electron distribution, the outermost orbital can contain a maximum of 8 electrons.

What is the Octet rule?

When atoms have fewer than eight electrons, they tend to react and form more stable compounds. The octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell. This is referred to as the Octet state, which is a stable state.

Electronic configuration

For example, the electronic configuration of oxygen is (2,6). An oxygen atom has six electrons in its outermost shell and has to borrow or share electrons with atoms of other elements to achieve the stable octet state.

Electronic configuration of oxygen

What is Valency?

Donating or accepting or even sharing of electrons between the atoms of elements gives rise to formation of chemical bonds and results in a compound.

And it is the concept of valency that determines how many electrons are to be given, or accepted or shared by an atom. In the above case, oxygen requires 2 electrons to achieve the octet state. Hence, the valency of oxygen is 2.

Valency is the reason that elements like hydrogen and oxygen are capable of reacting with several other elements and elements like helium, neon, argon and xenon do not participate in reactions.