How many electrons are in the outer shell of calcium

Calcium has two electrons on its outer shell or energy level.

An energy level also known as electron shell, or just shell is a location around an atom where electrons with a specific energy value, or quantum number may be found.

Calcium has four energy levels with a total of 20 electrons

In the periodic table calcium is found in the second column with other elements such as magnesium and beryllium.

They all have an outer shell with two electrons and are known to be very reactive. They are very ready to make new compounds with other elements.

Calcium therefore is said to have a valence of 2