Total number of electrons present in `piMOs` in `B_(2)` molecule is

Explanation

To determine the total number of electrons present in the π molecular orbitals (MOs) of the B₂ molecule, we can follow these steps:

### Step 1: Determine the electron configuration of Boron
Boron (B) has an atomic number of 5, which means it has 5 electrons. The electron configuration of a single boron atom is:
- 1s² 2s² 2p¹

### Step 2: Calculate the total number of electrons in B₂
Since B₂ consists of two boron atoms, we multiply the number of electrons in one boron atom by 2:
- Total electrons in B₂ = 5 electrons (from one B) × 2 = 10 electrons.

### Step 3: Write the molecular orbital configuration for B₂
The molecular orbital (MO) configuration for B₂ can be arranged as follows:
1. σ1s²
2. σ*1s²
3. σ2s²
4. σ*2s²
5. π2p_x² (or π2p_y²)
6. σ2p_z²
7. π*2p_x (or π*2p_y)
8. σ*2p_z

### Step 4: Fill the molecular orbitals with the total electrons
We fill the molecular orbitals in order of increasing energy:
1. σ1s² - 2 electrons
2. σ*1s² - 2 electrons
3. σ2s² - 2 electrons
4. σ*2s² - 2 electrons
5. π2p_x² and π2p_y² - 4 electrons (2 in each)
6. σ2p_z - 0 electrons (not filled)
7. π*2p_x and π*2p_y - 0 electrons (not filled)
8. σ*2p_z - 0 electrons (not filled)

### Step 5: Identify the electrons in π molecular orbitals
In the molecular orbital configuration, the π molecular orbitals are:
- π2p_x and π2p_y (bonding)
- π*2p_x and π*2p_y (antibonding)

From the filling:
- π2p_x and π2p_y have 2 electrons each, totaling 4 electrons in the bonding π orbitals.
- The π* orbitals are empty.

### Conclusion
The total number of electrons present in the π molecular orbitals (bonding) of the B₂ molecule is **4 electrons**.