# What is the electron configuration of palladium?

Nov 13, 2015

""_46Pd: 1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 4s^2, 3d^(10), 4p^6, 5s^(color(red)(0)), 4d^(color(green)(10).

#### Explanation:

The atomic number of Palladium is $46$, therefore,

""_46Pd: 1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 4s^2, 3d^(10), 4p^6, 5s^2, 4d^(8)

You can write the electron configuration using the Aufbau principle triangle:

However, the experiment has shown that the electron configuration of Palladium is:
""_46Pd: 1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 4s^2, 3d^(10), 4p^6, 5s^(color(red)(0)), 4d^(color(green)(10).

The answer is more complicated than a student at the AP chemistry level would understand, I will just give couple of reasons that will simplify the question:

1. Full $d$ orbitals are more stable than partially filled ones.
2. At higher energy levels, the levels are said to be degenerated which means that they have very close energies and then electrons can jump from one orbital to another easily.