Oxygen Electron Configuration: 7 (Easy Step-by-Step Guide)

Oxygen is placed in the 2nd-period and group -16 in the periodic table based on its electron configuration. Let us explore different facts on its electron configuration.

The electron configuration of Oxygen (O) will be 1s2 2s2 2p4. Oxygen is a nonmetal gaseous substance that is also known as a p-block element. It has an atomic number of 8 and is placed after nitrogen in the periodic table. It is one of the most electronegative elements with an electronegativity value of 3.44.

This article gives a clear discussion of the ground state as well as the excited state electron configuration, notation, an orbital diagram of oxygen along with the electron configuration of singlet oxygen.

How to write oxygen electron configuration?

Oxygen contains a total 8 number of electrons in its two electronic shells (K and L). These 8 electrons start filling in those shells having lower energy to higher energy using Aufbau’s principle, Hund’s multiplicity rule, and Pauli’s exclusion principle.

  • First, determine the number of electronic shells or orbitals required to accommodate 8 electrons.
  • To place these 8 electrons, 1s, 2s and 2p orbitals are introduced and start filling those orbitals.
  • Therefore, the first two electrons will enter 1s orbital and orient themselves in antiparallel spin obeying Hund’s rule.
  • Two of the remaining six electrons enter 2s, and the rest of the four electrons enter the 2p orbital.
  • These numbers of electrons are written as the superscript beside the orbitals like 1s2 2s2 etc.
  • Thus, the electron configuration of oxygen will be 1s2 2s2 2p4.     

Oxygen Electron Configuration Diagram

An Oxygen electron configuration diagram can be drawn by applying the Aufbau principle. In oxygen, the 1s orbital will be filled first followed by 2s and 2p orbital because the increasing order of energy of these orbitals is 1s < 2s < 2p.

oxygen electron configuration
Aufbau Principle

Oxygen Electron Configuration Notation

The electron configuration notation of O is [He] 2s2 2p4.

  • In this notation [He] denotes the electron configuration of the helium atom. It has a total of 2 electrons.
  • S and p indicate the two orbitals in which the shape of s and p orbital is spherical and dumble shaped respectively.
  • The number 1 and 2 before s and p denotes the principal quantum number or the energy states.
  • The superscripts 2 and 4 are the number of electrons.

Oxygen Unabbreviated Electron Configuration

The unabbreviated electron configuration of O is 1s2 2s2 2p4.

Ground State Oxygen Electron Configuration

The ground state electron configuration of O is 1s2 2s2 2p4 or [He] 2s2 2p4.

Oxygen Electron configuration 1
Oxygen ground state electron configuration

Excited State of Oxygen Electron Configuration

The excited state electron configuration of O is 1s2 2s2 2p3 3s1. The difference between the electron configuration of the excited and ground state is that 1 electron from the 2p orbital is excited due to chemical or photochemical reasons and transferred to the slightly higher energized 3s orbital.

Oxygen Excited state Electron configuration
Oxygen excited state electron configuration

Ground State Oxygen Orbital Diagram

The ground state orbital diagram of O indicates the procedure of filling the 8 electrons in the electronic shells (K, L, M, etc) around the nucleus. K orbital can accommodate 2 electrons in itself. L orbital will place the rest of the 6 electrons though it has the maximum capacity of placing 8 electrons.

Oxygen Orbital Diagram 1
Oxygen orbital diagram

Oxygen 2- Electron Configuration

The electron configuration of O (2-) is 1s2 2s2 2p6 because O2- has two more electrons than the neutral oxygen atom. These extra 2 electrons are placed in the 2p orbitals and gain the stability of fulfilled electron configuration because all the orbitals are filled with their maximum capacity.

Singlet Oxygen Electron Configuration

The electron configuration of singlet oxygen is shown below in σπ the following diagram-

Singlet oxygen
Molecular Orbital Diagram of Singlet Oxygen

Conclusion

The determination of the electron configuration of any atom is very much significant. It decides the magnetic behavior as well as the physical and chemical properties of any atom. It also helps to place the elements in the actual position of the periodic table.

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