The model below shows a calcium atom. how many electrons are in the third energy level? 2 8 18 20

Answer;

- 8 electrons

Explanation;Calcium is an alkaline earth metal in group 2 of the periodic table. Calcium has an atomic number of 20, which means it has 20 protons and 20 electrons on the energy levels.Calcium electronic configuration would have electrons occupying four energy levels, the first one having 2 electrons, the second having 8 electrons, the third having 8 electrons and the forth or the last having 2 electrons.It has two valence electrons, thus has a valency of two, since it has two electrons in its outermost energy level.