Chemistry

Question Analysis
This question evaluates the student's understanding of electron configuration and the application of the Aufbau principle, Pauli exclusion principle, and Hund’s rule.

Key Concept Explanation
Electron configuration describes the distribution of electrons in atomic orbitals. Phosphorus has 15 electrons, which must be filled according to the energy order: 1s → 2s → 2p → 3s → 3p.

Step-by-step Solution
1. Identify the total number of electrons: Phosphorus (P) has 15 electrons.
2. Fill the orbitals in the correct order: 1s (2 electrons) → 2s (2 electrons) → 2p (6 electrons) → 3s (2 electrons) → 3p (remaining 3 electrons).
3. Write the electron configuration: