`O_2` molecule is paramagnetic in

Options

A. solid state
B. liquid state
C. gaseous state
D. All of these

Explanation

To determine the paramagnetic nature of the `O_2` molecule, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Oxygen Atom Configuration**:
- Oxygen (O) has an atomic number of 8, which means it has 8 electrons. The electron configuration of oxygen is `1s² 2s² 2p⁴`.

2. **Molecular Formation**:
- In the `O_2` molecule, two oxygen atoms combine. Each oxygen atom contributes 6 valence electrons (2 from the `2s` and 4 from the `2p` subshells).
- When two oxygen atoms bond, they form a double bond, resulting in the sharing of two pairs of electrons.

3. **Electron Arrangement in `O_2`**:
- The molecular orbital theory can be applied here. In the molecular orbital diagram for `O_2`, the electrons fill the molecular orbitals as follows:
- The bonding orbitals (σ and π) are filled first, followed by the antibonding orbitals (σ* and π*).
- The configuration in the molecular orbitals for `O_2` is:
- σ(1s)², σ*(1s)², σ(2s)², σ*(2s)², σ(2p_z)², π(2p_x)², π(2p_y)², π*(2p_x)¹, π*(2p_y)¹.

4. **Identifying Unpaired Electrons**:
- In the molecular orbital configuration of `O_2`, we can see that there are two unpaired electrons in the π*(2p_x) and π*(2p_y) orbitals.
- The presence of unpaired electrons is a key factor in determining paramagnetism.

5. **Conclusion on Paramagnetism**:
- Since `O_2` has unpaired electrons, it exhibits paramagnetic behavior. This means that it is attracted to magnetic fields.
- This paramagnetic nature is consistent across all states of matter: solid, liquid, and gaseous.

### Final Answer:
The `O_2` molecule is paramagnetic in all states: solid, liquid, and gaseous.

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