Question

How many excited electron in the atom with an electron configuration of [kr]5s24d55p6 ?

Answer 1

The ground-state electronic configuration follows the order of orbitals as shown in the first picture. So, we can deduce that the electronic configuration given is in order. However, each orbital must have a maximum number of electrons to be filled before it can move on to the next orbital. Since the d orbital must hold 10 electrons, that means that it should have held 5 electrons more. The missing 5 electrons were excited to the next 5p orbital. Thus, there are 5 excited electrons.