State Hund's rule of maxium multiplicity. How is it used in electronic distribution in nitrogen atom `(Z=7)`?

Answer

### Step-by-Step Solution

**Step 1: State Hund's Rule of Maximum Multiplicity**
Hund's rule of maximum multiplicity states that in a given subshell, electrons will occupy degenerate orbitals (orbitals of the same energy) singly first, before any pairing occurs. Furthermore, all singly occupied orbitals will have electrons with the same spin (parallel spins). This arrangement minimizes electron-electron repulsion and leads to greater stability.

**Step 2: Apply Hund's Rule to the Nitrogen Atom**
The atomic number of nitrogen (N) is 7, which means it has 7 electrons. The electronic configuration of nitrogen can be written as follows:
- The first two electrons fill the 1s orbital: **1s²**
- The next two electrons fill the 2s orbital: **2s²**
- The remaining three electrons will occupy the 2p orbitals.

**Step 3: Distribute Electrons in the 2p Orbitals**
The 2p subshell consists of three degenerate orbitals (2p_x, 2p_y, and 2p_z). According to Hund's rule:
- The first electron goes into the 2p_x orbital.
- The second electron goes into the 2p_y orbital.
- The third electron goes into the 2p_z orbital.

All three electrons in the 2p orbitals will have parallel spins, resulting in the configuration: **2p³**.

**Step 4: Summarize the Electronic Configuration**
The complete electronic configuration of nitrogen is:
- **1s² 2s² 2p³**

This configuration is stable due to the half-filled 2p subshell, which is in accordance with Hund's rule.