Chemical symbol: Ca
Atomic number: 20
Atomic mass: 40.079
Group: 2 (Alkali earth metals)
Period: 4
Element category: Alkali earth metals
Block: s-block
Number of protons: 20
Number of electrons: 20
Number of neutrons (in the most common isotope): 20
Sources:
Knowledge Encyclopedia (book)
SCIENCIA (book)