Question

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

Answer 1

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.

Answer 2

Answer: The correct answer is 8.

Step-by-step explanation:

Calcium is the 20th element of the periodic table. The number of electrons in this element are 20. So, the electronic configuration of this element is:
`1s^22s^22p^63s^23p^64s^2`

The third energy level is the level which has n = 3 and the number of electrons that are present in n = 3 are ( 2+ 6) = 8 electrons.

Hence, 8 electrons are there in the third energy level.