How many core electrons and how many valence electrons do atoms of Se possess?

Question

Quizplus · Accepted Answer

Selenium (Se) has an atomic number of 34, meaning it has 34 electrons in its neutral state. The electron configuration of Se can be written as [Ar] 3d^10 4s^2 4p^4. The electrons in the [Ar] core and the 3d^10 orbitals are considered core electrons, totaling 28 (18 from [Ar] and 10 from 3d^10). The remaining 4s^2 and 4p^4 electrons, totaling 6, are the valence electrons.

How Many Core Electrons and How Many Valence Electrons Do