This answer will be generalized so that it can be used for any element.
Locate the element you are looking for on the periodic table. Two numbers should appear in the box containing an element’s chemical symbol. The atomic number is the smallest number. It denotes how many protons the element contains. The average atomic mass for an element is the largest. The actual atomic mass of an element can vary depending on how many neutrons it contains. Atoms that have the same number but different numbers of neutrons are known as isotopes. Simply subtract the atomic number from atomic mass to calculate how many neutrons are in an isotope. Take this example:
16 Atomic number = Number of protons. 32Atomic mass = Number of protons and neutrons.
Number of neutrons = 32 + 16 = 16
The number of electrons in a neutral atom is equal to the number protons. Each of the sulfur isotopes will have 16 electrons. A positive ion will also have fewer electrons than a negative one.
Et voila, happy counting!