Question

The following ground-state electron configuration of potassium shows that for the ground state of the potassium atom the outermost electron is in a 4s state: 1s^2 2s^2 2p^6 3s^2 3p^6 4s This tells you that, compared to the 3d level for this atom, the 4s level ANSWER: has a lower energy. has approximately the same energy. has a higher energy.

Answer 1

The 4s sublevel is only lower in energy if there are no electrons in the 3d sublevel. According to the Aufbau principle, the 4s sublevel is filled before the 3d sublevel because the 4s is lower in energy. As the 3d sublevel becomes populated with electrons, the relative energies of the 4s and 3d fluctuate relative to one another and the 4s ends up higher in energy as the 3d sublevel fills. This is why when electrons are lost from the orbitals of the transition metals, they are lost from the 4s first because it is higher in energy.

So, 4s has lower energy than 3d orbital as it is empty in case of potassium.

Option 1