The paramagnetic property of the oxygen molecule is due to the presence of unpiared electrons present in .

Options

A. `(pi^(**) 2p_(y))^(1) and (pi^(**)2p_(x))`
B. `(sigma2p_(z))^(1) and (sigma^(**)2p_(z))^(1)`
C. `(pi2p_(y))^(1) and (pi^(**)2p_(y))^(1)`
D. `(sigma2p_(z))^(1) and (pi2p_(y))^(1)`

Answer

To determine the paramagnetic property of the oxygen molecule (O₂) due to the presence of unpaired electrons, we can follow these steps:

### Step 1: Understand the Electron Configuration of Oxygen
Oxygen has an atomic number of 8, which means each oxygen atom has 8 electrons. The electron configuration for a single oxygen atom is:
- 1s² 2s² 2p⁴

### Step 2: Combine the Electron Configurations for Two Oxygen Atoms
When two oxygen atoms combine to form the O₂ molecule, we consider the valence electrons (the electrons in the outermost shell). Therefore, we focus on the 2s and 2p orbitals:
- Total valence electrons for O₂ = 2 (from the first O) + 2 (from the second O) + 4 (from the 2p of both O) = 12 valence electrons.

### Step 3: Draw the Molecular Orbital Diagram
In the molecular orbital theory, the atomic orbitals combine to form molecular orbitals. The molecular orbitals for O₂ are filled in the following order:
1. σ(2s) - bonding
2. σ*(2s) - antibonding
3. σ(2p_z) - bonding
4. π(2p_x) and π(2p_y) - bonding
5. π*(2p_x) and π*(2p_y) - antibonding

### Step 4: Fill the Molecular Orbitals with Electrons
Following the Aufbau principle, Hund's rule, and the Pauli exclusion principle, we fill the molecular orbitals with the 12 electrons:
- σ(2s) = 2 electrons
- σ*(2s) = 2 electrons
- σ(2p_z) = 2 electrons
- π(2p_x) = 2 electrons
- π(2p_y) = 2 electrons
- π*(2p_x) = 1 electron
- π*(2p_y) = 1 electron

### Step 5: Identify Unpaired Electrons
From the filling of the molecular orbitals, we can see that the π*(2p_x) and π*(2p_y) orbitals each contain one unpaired electron. Thus, O₂ has two unpaired electrons.

### Step 6: Conclude the Paramagnetic Property
The presence of unpaired electrons in the π*(2p_x) and π*(2p_y) orbitals is responsible for the paramagnetic property of the oxygen molecule. Therefore, the answer to the question is that the unpaired electrons are present in the π* (pi star) molecular orbitals.

### Final Answer:
The paramagnetic property of the oxygen molecule is due to the presence of unpaired electrons present in the π*(2p_x) and π*(2p_y) orbitals.

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