Which of the following is the composition of an isotope of calcium (atomic number 20)?
22 protons, 20 neutrons, 19 electrons
19 protons, 20 neutrons, 19 electrons
20 protons, 25 neutrons, 20 electrons
21 protons, 20 neutrons, 20 electrons
- Lexi RLv 77 years agoFavorite Answer
the atomic number of an atom defines what element the atom is.
It is the number of protons on the nucleus of the atom.
The atomic number of Ca is 20, therefore it has 20 protons. Any atom that has 20 protons will always be a Ca atom.
so the answer is
20 protons, 25 neurons, 20 electrons