H.O.M.O (Highest Occupied Molecular Orbital ) of CO molecular is :

Options

A. Non-bonding M.O. with slight antiboding character
B. Non-bonding M.O. with slight boding character
C. Pure non-bonding M.O.
D. None of above

Explanation

To determine the Highest Occupied Molecular Orbital (HOMO) of the carbon monoxide (CO) molecule, we will follow these steps:

### Step 1: Identify the Atomic Orbitals
- Carbon (C) has the electron configuration: 1s² 2s² 2p².
- Oxygen (O) has the electron configuration: 1s² 2s² 2p⁴.

### Step 2: Construct the Molecular Orbital Diagram
- CO is a heteronuclear molecule, meaning it consists of two different atoms (C and O).
- The molecular orbitals are formed by the combination of atomic orbitals from both atoms.
- The order of energy levels for the molecular orbitals in CO is as follows:
- σ(1s), σ*(1s), σ(2s), σ*(2s), σ(2p), π(2p), π*(2p), σ*(2p).

### Step 3: Fill the Molecular Orbitals with Electrons
- Fill the molecular orbitals according to the Aufbau principle, Pauli exclusion principle, and Hund's rule.
- For CO, we have a total of 10 valence electrons (4 from C and 6 from O).
- The filling order will be:
- σ(1s) - 2 electrons
- σ*(1s) - 0 electrons
- σ(2s) - 2 electrons
- σ*(2s) - 0 electrons
- σ(2p) - 2 electrons
- π(2p) - 4 electrons (2 in each of the two π orbitals)

### Step 4: Determine the Highest Occupied Molecular Orbital (HOMO)
- After filling the molecular orbitals, we find that the last filled orbitals are the π(2p) orbitals.
- Thus, the HOMO for CO is the π(2p) molecular orbital.

### Step 5: Analyze the Character of the HOMO
- The π(2p) orbital has non-bonding character with slight anti-bonding character due to the presence of the oxygen atom, which is more electronegative than carbon.
- Therefore, the HOMO of CO is best described as a non-bonding molecular orbital with slight anti-bonding character.

### Final Answer
The HOMO of the CO molecule is a non-bonding MO with slight anti-bonding character.

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