Atomic numbers are determined by the number of protons an atom has. The mass number is determined by the number of protons and neutrons. While the number of protons can't change (as the element itself would change), neutrons can and do vary. These are called isotopes.
The atomic number of calcium is 20.
The atomic number of calcium is 20.
The atomic number of Calcium is 20.
Calcium is a metal element. atomic number of it is 20.
The number of neutrons is the difference between the Atomic Mass of an isotope and the atomic number of the element; each isotope of calcium has a different number of neutrons. See the link below for calcium isotopes.
Because different elements have different numbers of protons, which determines the atomic number.
Calcium is a meta element. Atomic number of it is 20.
Calcium
The different mass numbers are due to different numbers of neutrons.
Isotopes have different numbers of electrons, but not different atomic numbers (numbers of protons) or they'd be different elements.
The most common calcium isotope, calcium-40, has 20 neutrons.
The element Calcium (Ca) has 20 electrons according to its atomic number which is 20.