If an atom has an atomic number of 8 and a mass number of 18, how many protons, neutrons, and electrons are in the atom?

the law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. because atoms are only rearranged in a chemical reaction, there must be the same number of sodium atoms and chlorine atoms in both the reactants and products

c) should be the answer.