Explain electronic configuration in detail

Electronic configuration is defined as the distribution of electrons into various orbitals of an atom by using three principles.

Aufbau principle states that in the ground state of the atoms the orbitals are filled in order of their increasing energies. Electrons first occupy the lowest-energy orbital and then enter into successive higher energy orbitals. The electrons enter into various orbitals in an increasing order of (n+l).

Pauli's Exclusion Principle states that: An orbital can have maximum two electrons with opposite spin.

Hund's Rule of Maximum Multiplicity states that: Electron pairing in p, d and f orbitals cannot occur until each orbital of a given sub-shell contains one electron each or is singly occupied.

• We can represent the electronic configuration of atoms in two ways.
• Orbital diagram method
• nlx method

Electronic configuration of the first ten elements - Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine, and Neon given in following table.

After filling the 2p orbitals, the electrons fill into the 3s and then the 3p orbitals.

The electronic configurations of most of the elements can be write in a simplified manner or condensed form.

The eleventh electron in Sodium will enter the 3s orbital. Therefore, the electronic configuration of Sodium can also be written in a condensed form as [Ne] 3s¹.

Following table gives condensed form for elements from Sodium to Potassium.