What is the electron configuration for the element with atomic number 19?

The element with atomic number 19 is potassium (K). To determine its electron configuration, we consider how many electrons it has, which corresponds directly to its atomic number. Thus, potassium has 19 electrons.

We build the electron configuration by filling the orbitals in order of increasing energy levels according to the Aufbau principle. The general order for filling is 1s, 2s, 2p, 3s, 3p, and then 4s.

1. The 1s orbital can hold 2 electrons: 1s²

2. The 2s orbital can also hold 2 electrons: 2s²

3. The 2p subshell can hold a maximum of 6 electrons; since we fill it entirely, it will be: 2p⁶

4. The 3s subshell now can hold 2 electrons: 3s²

5. The 3p subshell can hold 6 electrons, which means we can fill it completely: 3p⁶

6. Finally, the 4s subshell will hold 2 electrons: 4s²

So far, we have accounted for 2 + 2 +