To determine which electron configuration matches the nitrogen atom, let's follow the steps to obtain the correct electron configuration.
1. Identify the atomic number of nitrogen: The atomic number of nitrogen (N) is 7. This means that a nitrogen atom has 7 protons and, in a neutral atom, it also has 7 electrons.
2. Determine the electron configuration:
- The electron configuration of an atom describes the distribution of its electrons among the available energy levels (or shells) and sublevels (or orbitals).
- Electrons will fill the lowest energy levels first before moving to higher energy levels. This is guided by the Aufbau principle.
3. Apply the Aufbau principle, Hund's rule, and the Pauli exclusion principle to distribute these 7 electrons among the orbitals:
- The 1s orbital can hold a maximum of 2 electrons. So, the first 2 electrons will go into the 1s orbital: `1s²`.
- The 2s orbital can also hold a maximum of 2 electrons. Thus, the next 2 electrons will enter the 2s orbital: `2s²`.
- After the 1s and 2s orbitals are filled, we have 3 electrons left to place. These will go into the 2p orbitals. The 2p sublevel has 3 degenerate (same energy) orbitals, and they are each filled singly before any pairing occurs (Hund’s rule). Therefore, the next 3 electrons will enter the 2p orbitals: `2p³`.
Putting it all together, the electron configuration for nitrogen (N) is:
```
1s² 2s² 2p³
```
Therefore, the electron configuration that matches the nitrogen atom is:
```
1s² 2s² 2p³
```
Thus, the correct choice from the given options is:
```
O 1s² 2s² 2p³
```
