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:

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

• Pauli Exclusion Principle: No two electrons in an atom can have the same set of four quantum numbers; 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, and all electrons in singly occupied orbitals have the same spin.

• Electron Configuration for Nitrogen (Z = 7): 1s2 2s2 2p3

Step-by-Step Guidance

1. Determine the total number of electrons in a neutral nitrogen atom. Since nitrogen has an atomic number of 7, it has 7 electrons.

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

3. Draw the orbital diagram for each subshell:

   • 1s: two electrons (paired, opposite spins)

   • 2s: two electrons (paired, opposite spins)

   • 2p: three electrons (Hund's Rule applies—each p orbital gets one electron before any pairing occurs, and all have the same spin)

4. Compare each provided diagram to see which one matches the correct filling order and spin arrangement for nitrogen.

Try solving on your own before revealing the answer!