What is the term for the distribution of electrons among available orbitals in an atom?

• A. Electron configuration
• B. Pauli Exclusion Principle
• C. Hund's Rule
• D. Avogadro's number

Answer: (A)

The main idea here is how electrons occupy the available orbitals around the nucleus. The term for that overall arrangement is electron configuration. It describes the number of electrons in each orbital and subshell, giving a picture of the atom’s electronic structure. In practice, this distribution follows rules like the Aufbau principle, which guides the order in which orbitals are filled; the Pauli exclusion principle, which limits each orbital to two electrons with opposite spins; and Hund's rule, which says electrons will occupy degenerate orbitals singly before pairing. Avogadro's number is unrelated to how electrons are arranged in orbitals, since it’s simply the number of particles in a mole.