`O_2` molecule is

Options

A. paramagnetic
B. diamagnetic
C. ferromagnetic
D. none of these

Answer

To determine whether the O₂ molecule is paramagnetic, diamagnetic, or ferromagnetic, we can follow these steps:

### Step 1: Determine the Electronic Configuration of Oxygen
Oxygen (O) has an atomic number of 8. Its electronic configuration is:
- 1s² 2s² 2p⁴

### Step 2: Draw the Molecular Orbital Diagram
We need to construct the molecular orbital (MO) diagram for O₂. The molecular orbitals are formed by the combination of atomic orbitals from the two oxygen atoms.

1. **2s Orbitals**:
- Two 2s orbitals combine to form one bonding orbital (σ2s) and one antibonding orbital (σ*2s).

2. **2p Orbitals**:
- The 2p orbitals combine to form:
- One bonding orbital (σ2p) from the 2pz orbitals.
- Two degenerate bonding orbitals (π2p) from the 2px and 2py orbitals.
- Corresponding antibonding orbitals (σ*2p and π*2p).

### Step 3: Fill the Molecular Orbitals with Electrons
Now, we fill the molecular orbitals with the total number of electrons in O₂, which is 16 (8 from each oxygen atom).

1. Fill the σ2s and σ*2s orbitals with 2 electrons each.
2. Fill the σ2p orbital with 2 electrons.
3. Fill the π2p orbitals with 4 electrons (2 in each).
4. The remaining 2 electrons will go into the π*2p orbitals (one in each, following Hund's rule).

### Step 4: Count the Unpaired Electrons
After filling the molecular orbitals, we observe the following:
- σ2s: 2 electrons (paired)
- σ*2s: 0 electrons
- σ2p: 2 electrons (paired)
- π2p: 4 electrons (2 pairs)
- π*2p: 2 electrons (1 unpaired in each of the two π* orbitals)

### Conclusion
Since there are unpaired electrons in the π*2p orbitals, the O₂ molecule is **paramagnetic**.

### Final Answer
The O₂ molecule is **paramagnetic**.

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