The answer is 2 electrons.
The electron configuration of calcium is 2:8:8:2
Calcium has two electrons in its outermost shell. These are its valence electrons and are the ones used in bonding with other elements. Valence electrons of an atom are those electrons that are in its outer energy shell or that are available for bonding.
Calcium is a metal. When metals react with non-metals, electrons are transferred from the metal atoms to the non-metal atoms forming ions. The resulting compound is known as an ionic compound.
For example, when calcium metal reacts with chlorine gas, calcium gives up its two valence electrons and Chlorine accepts them resulting in a new substance called calcium chloride in which the two elements have ended up forming ionic bonds.
To figure out the ratios of these compounds, it is important to remember that the charge of these compounds must be <em>
neutral</em>.
So in order to make them neutral, you must have specific ratios:

; This is true because they both have a charge of magnitude of 1.

; We need 3 chlorine atoms because we need to balance out the charge from the 3+ charge of aluminum - therefore since chlorine has a 1- charge, we need 3 atoms.

; The charges of the magnesium (2+) are balanced with the oxygen charge (2-).

; This is correct because if charges are like this, you must find the least common factor in order to know the ratio. The LCF is 6, therefore, for the atom with a 3+ charge, you need 2 of them, and for the atom with a 2- charge, you need 3 of them. This keeps the charge neutral.
the law that the product of the pressure and the volume of one gram molecule of an ideal gas is equal to the product of the absolute temperature of the gas and the universal gas constant.
Answer:
all matter (everything) is made of the elements on the periodic table
Explanation:
The charge of an ion of calcium that loses two electrons is D.) +2
hope this helps you