Number of protons n one atom of Calcium 39 is 20.
Number of protons in any element is equal to its atomic number. Since the atomic number of calcium is 20, hence, the number of protons is also 20. To balance the positive charge, the atoms contain same number of electrons. Thus, number of electrons in given atom of calcium will also be 20.
The number of neutrons is calculated by performing subtraction between mass number and number of protons. The number of neutrons is indicative of the isotope of atom, as it changes with the mass of an atom.
Calcium is an alkaline earth metal. The smallest unit of matter is atom which can occur either in neutral state or in ionized state.
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