The electron affinity of nitrogen is zero.

Answer

**Step-by-Step Solution:**

1. **Understanding Electron Affinity:**
- Electron affinity is defined as the amount of energy released when an electron is added to a neutral atom in the gas phase to form a negative ion (anion).

2. **Identifying the Atomic Structure of Nitrogen:**
- The atomic number of nitrogen (N) is 7. This means it has 7 electrons.
- The electronic configuration of nitrogen is 1s² 2s² 2p³.

3. **Analyzing the 2p Subshell:**
- In the 2p subshell, nitrogen has three electrons, which occupy the three available p orbitals (2p_x, 2p_y, 2p_z) singly. This configuration is represented as 2p³.
- A half-filled subshell (like 2p³) is particularly stable due to symmetry and exchange energy.

4. **Stability of Nitrogen:**
- Since the 2p subshell in nitrogen is half-filled, it is in a more stable state. Atoms tend to prefer configurations that minimize energy, and a half-filled p subshell is energetically favorable.

5. **Conclusion on Electron Affinity of Nitrogen:**
- Because nitrogen is already in a stable configuration, it does not favor the addition of an electron. Adding an electron would disrupt this stability and lead to the formation of a negatively charged ion (N⁻), which is less stable.
- Therefore, the energy change associated with adding an electron to nitrogen is negligible, resulting in an electron affinity of zero.

**Final Statement:**
Thus, the electron affinity of nitrogen is zero because it is already in a stable half-filled configuration and does not require additional electrons.

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