Question

Why is the electron configuration for copper 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹ instead of 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁹ 4s²? The arrangement of electrons with the same spin is as small as possible. The 4s orbital has higher energy than the 3d orbital. A filled sublevel is more stable than a half-filled sublevel. Electrons occupy orbitals of the highest energy levels first.

a. Spin Rule
b. Energy Level Rule
c. Stability Rule
d. Not Mentioned

Answer 1

The electron configuration for copper is determined by the Stability Rule, which states that a filled sublevel is more stable than a half-filled sublevel.

Step-by-step explanation:

The electron configuration for copper is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹ instead of 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁹ 4s² because of the Stability Rule. In the case of copper, a filled sublevel (3d subshell) is more stable than a half-filled sublevel (3d⁹). Therefore, an electron from the 4s orbital moves to the 3d orbital to achieve a more stable configuration.