Question

The atomic weight of calcium is _______.

Answer 1

Atomic weight:

• The total weight of an atom equals its atomic mass or atomic weight.
• It is approximately equal to the number of protons and neutrons, with a little extra added by the electrons because electrons are of negligible mass as compared to protons and neutrons.
• Example; the atomic weight of hydrogen is 1.0079 and that of carbon is 12.011.

Calcium:

• Calcium is a chemical element having a chemical symbol $\mathrm{Ca}$ with the atomic number 20.
• It belongs to the group of alkaline earth metals of group 2nd of the periodic table.
• It contains 20 electrons which are equal to the number of protons in it.
• Since, it is a stable atom having a net charge of zero, therefore, the number of neutrons will be the same as the number of protons which is 20. Hence, the atomic mass/ atomic weight of calcium comes out to be equal to 40.078 u.

Thus, the atomic weight of calcium is 40.078 u.