How many electrons does calcium have?

Hint: Calcium is a group 2 element with the atomic number 20 and mass number 40 g/mol. Atomic number is the total number of protons present in an atom and mass number is the sum of the total number of neutrons and protons present in the atom.

Complete answer:
- Calcium is an alkaline earth metal, since it belongs to the s block of the periodic table.
- The chemical symbol of calcium is “Ca”, with the atomic number being 20. The atomic mass of calcium is 40 g/mol.
- Calcium is an element of the second group on the modern periodic table. It has the tendency to lose electrons to acquire the nearest noble gas electronic configuration.
- The atomic number is the total charge on the nucleus while the mass number is the weight of the nucleus.
- Now, calcium has mass number 40 and atomic number 20.
- We know that, number of protons is the same as that of the number of electrons required to keep the atom electrically neutral. Also, the atomic mass is the same as the number of neutrons and protons present within the atom.
- In calcium atom,
Number of protons = 20
Number of neutrons = atomic mass – number of protons
Number of neutrons = 40 – 20 = 20

Therefore, the total number of electrons present in calcium is 20.

Note: It should be noted that the number of electrons is always equal to the number of protons to keep the element electrically neutral. But the number of neutrons may or may not be equal to the number of electrons and protons.