Question

The sequence of filling electrons in different shells is determined by:

• A. Octet rule
• B. Hund's rule
• C. Aufbau rule
• D. All the above

Answer 1

The correct option is C Aufbau rule

The octet rule is used to explain the stable configuration attained by sharing electrons in covalent compounds.
Hund's rule says that all the degenerate states must be singly filled with the same spin before any pairing.
Aufbau's principle describes the order for filling of orbitals from lower energy to higher energy.