Which subshell is filled after the 5s subshell in the order of electron configurations?

After the 5s subshell is filled in the order of electron configurations, the next subshell to be filled is the 4d subshell. This follows the principles of the Aufbau principle, which states that electrons fill atomic orbitals in order of increasing energy levels.

In the case of transition metals, as you begin filling the 5s subshell, the 4d subshell is next in line due to its energy level being slightly higher than that of the filled 5s but lower than that of 5p. The order of filling also respects the Madelung energy ordering rule, which indicates that orbitals should be filled based on a combination of their principal quantum number (n) and their azimuthal quantum number (l).

Following the 5s, the filling sequence progresses to the 4d subshell before reaching the 5p subshell. This sequence is critical for understanding the electron configurations of transition metals and their properties, as the filling of the d orbitals plays a significant role in characteristic behaviors such as magnetism and the formation of colored compounds.