What are some common mistakes in electron configurations?

What are some common mistakes people make when writing electron configurations?

Some common mistakes include forgetting to fill the 4s subshell before the 3d subshell and not following the Aufbau principle.

Can you explain the Aufbau principle?

The Aufbau principle states that electrons occupy the lowest energy orbitals first before moving to higher energy levels.

What about the Pauli exclusion principle?

The Pauli exclusion principle states that no two electrons in an atom can have the same set of four quantum numbers.

How do these principles affect the electron configuration of transition metals?

In transition metals, the 3d and 4s orbitals are very close in energy, which can lead to exceptions in their electron configurations.