For most atoms, there are the same number of electrons as there are protons. When you write down the formula of a compound, you usually write down a list of symbols. For example, when you write down the formula for water, you write H 2 0. An atom's mass is the total mass of all of the little parts inside the atom. You should know that one neutron has a mass about as much as one proton.
Electrons have a very small mass compared to all of the other parts in an atom.
If you want to figure out the number of neutrons in an atom, you have to do a little subtraction. In Biology atoms are used in every reaction and process, but they don't usually act alone. Atoms connect to each other to form compounds. Andrew Rader Studios, All rights reserved.