# Atomic Orbital Diagram for Oxygen

**Definition of atomic orbital diagram for oxygen:**

An orbital is the region of space around the nucleus within which the probability finding an electron of given energy is maximum. The diagram of this region gives the diagram of the orbital. The plot of angular wave function or square of angular wave functions give us the diagram of orbitals. These two plots vary only slightly.

## Atomic Structure and Chemical Bonding of Oxygen:

Energy levels of molecular orbital has determined practically by spectroscopic studies. The order of increasing energy in case of the diatomic homo-nuclear molecules of first and second period of the periodic table is as given below.

`sigma` 1s<`sigma^*` 1s<`sigma` 2s<`sigma^*` 2s<`pi` 2px=`sigma` 2py<`sigma` 2pz<`pi^*` 2px=`pi^*` 2py<`pi^*` 2pz

This order of energies of various molecular orbitals is valid for molecules or ion like, H_{2}, H_{2}^{+}, He_{2}^{+}, He_{2}, Li_{2}, Be_{2}, B_{2}, C_{2}, and N_{2} molecules.

The above diagram explains the molecular orbital energy level diagram for molecules of Oxygen and other heavier elements.

However, experimental evidence for oxygen and heavier diatomic molecules has shown that above sequence of energy levels of MOs is not correct. In case of these elements, the order of energy levels of `sigma`2pxm, `pi` 2px and `pi`2py is reversed. Thus the order of increasing energy of MOs for these molecules is as follows.

`sigma`1s <`sigma^*` 1s<`sigma`2s<`sigma^*` 2s<`sigma`2pz<`pi` 2px=`pi` 2py<`pi^*` 2px=`pi^*` 2py<`sigma^*` 2pz

This order of energies of various MOs is valid for molecules or ions like O_{2}, O_{2}^{-} (super oxide ion), O_{2}^{2-} (peroxide ion), Fe_{2} and Ne_{2}.

## Atomic Orbital Diagram for Oxygen:

Atomic orbital diagram for oxygen:

The electronic configuration of oxygen (Z=8) in the ground state is 1s^{2}2s^{2}2p^{4}. Each oxygen atom has 8 electrons; hence in O_{2}_{2} is as follows molecule there are 16 electrons. Therefore, the electronic configuration of O

O_{2}:KK(`sigma`2s )^{2}(`sigma^*`2s)(`sigma`2pz)^{2}(`pi`2px )^{2}=(`pi`2px )^{2}(`pi^*` 2px)^{1}=(`pi^*` 2py)^{1}

Here (`sigma`1s)^{2}(`sigma^*`1s) part of the configuration is abbreviated as KK.

The molecular orbital energy level diagram of O_{2} molecule is as follows

The above diagram explains the molecular energy level diagram of atomic O_{2} molecule

Bond order = (N-N) / 2 = (8 – 4) / 2=4 / 2 =2