Identifying the Correct Electron Configuration for Nitrogen

Q5. Which one of the following is the correct electron configuration for a ground-state nitrogen atom?

Background

Topic: Electron Configurations and Orbital Diagrams

This question tests your understanding of how electrons fill atomic orbitals according to the Aufbau Principle, Pauli Exclusion Principle, and Hund's Rule. You are asked to identify the correct orbital diagram for a nitrogen atom in its ground state.

Key Terms and Concepts:

• Electron Configuration: The arrangement of electrons in an atom's orbitals.

• Aufbau Principle: Electrons fill the lowest energy orbitals first.

• Pauli Exclusion Principle: Each orbital can hold a maximum of two electrons with opposite spins.

• Hund's Rule: Every orbital in a subshell is singly occupied before any orbital is doubly occupied.

• Nitrogen (N): Atomic number 7, so it has 7 electrons in the ground state.

Step-by-Step Guidance

1. Determine the total number of electrons for nitrogen: 7 electrons.

2. Write the electron configuration for nitrogen: $1s^2\ 2s^2\ 2p^3$.

3. Recall that the 1s and 2s orbitals each hold 2 electrons (paired, opposite spins), and the 2p subshell will have 3 electrons.

4. Apply Hund's Rule: In the 2p subshell, each of the three 2p orbitals should have one electron before any pairing occurs. Each electron in the 2p orbitals should have parallel spins (all up or all down) before pairing.

5. Examine each diagram and check for: correct number of electrons, proper filling order, and correct application of Hund's Rule in the 2p orbitals.

Try solving on your own before revealing the answer!