Q28P - Chemistry: Molecular Nature Of Matter And Change

Question

How do the bonding and antibonding MOs formed from a given pair of AOs compare to each other with respect to

1. energy;
2.  presence of nodes;
3.  inter-nuclear electron density?

Step-by-Step Solution

Answer

Electrons in bonding orbitals stabilize they are between the nuclei. 

1. They also have lower energy because they are closer to the nuclei. Anti-bonding pi-orbital has higher energy levels and less electron density between nuclei.
2. There is a presence of nodes when the bonding and anti-bonding try bond then a node is created
3. The inter-nuclear electron density is stabilized.

Step 1: Bonding

Bonding may be defined as the attraction forced by both the atom on each other. In bonding there can be involvement of a pair of electron or two pair of electron. As per the pair of electron increases the attraction increases, hence, strong bond is formed. 

 

The bonding can be formed by sharing or completing giving the electron from one atom to another.

Step 2:Energy of the Molecular orbital

The molecular orbital is formed by the bonding of the two atomic orbital. The energy has higher energy in anti-bonding orbital than bonding orbital. The energy is lowest when there is bonding of two sigma orbital or two pi orbital by head-on-overlapping bonding and the energy is higher for the pi-orbital having side-ways-overlapping  density.

Step 3: Presence of Nodes

The nodes are the place where there is no electron present. The formation of a node is by the combination of two anti-bonding molecular orbitals.

Step 3: Inter-nuclear Electron Density

The orbitals of the atom are overlapped to form, the inter-nuclear electron density increases by sharing of electron.The electron density is high in this area and has repulsion between two electrons but there is a force of attraction of electron and nuclei with one to another electron and nuclei.