Question

13.kr 5s² 4d¹⁰5p³
explain what is wrong with the following electron configurations:
14.1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 4d¹⁰4p⁶
15.1s² 2s² 2p⁶ 3s³ 3d⁵

Explanation:

1. The order of filling sub - shells is incorrect. After 4d, the 5p sub - shell should be filled before writing the 5s electrons in this form. The correct order based on the Aufbau principle is [Kr]4d^{10}5s^{2}5p^{3}.
2. The 4d sub - shell cannot be filled before the 5s sub - shell. According to the Aufbau principle, electrons fill orbitals in order of increasing energy, and 5s has lower energy than 4d and should be filled first. The correct configuration would have 5s filled before 4d.
3. The 3s sub - shell can hold a maximum of 2 electrons. The notation 3s^{3} is incorrect as an s sub - shell has only one orbital and can hold a maximum of 2 electrons with opposite spins.

Answer:

1. Incorrect sub - shell filling order.
2. 4d filled before 5s contrary to Aufbau principle.
3. 3s sub - shell has more than maximum 2 electrons.