Question

question 2 of 25
in what order do electrons fill orbitals?
a. electrons fill orbitals in order of increasing orbital energy.
b. the p orbitals fill before the s orbitals in an energy level.
c. orbitals s, p, and then d fill in one energy level before starting the next level.
d. before pairing, 1 electron occupies each s and p orbital.

Explanation:

According to the Aufbau principle, electrons fill orbitals in order of increasing orbital energy. Option B is incorrect as s - orbitals fill before p - orbitals in an energy level. Option C is wrong because electrons fill sub - levels in a specific order across energy levels (e.g., 4s fills before 3d). Option D refers to Hund's rule about electron occupancy in degenerate orbitals, not the overall filling order.

Answer:

A. Electrons fill orbitals in order of increasing orbital energy.