The atomic number IS the number of protons. if you are given the mass number, then subtract the number of protons from it.
Number of neutrons + Number of protons
Find the atomic number. That tells you the number of protons and electrons (in a neutral atom). Then find the atomic weight. The number of protons plus the number of neutrons will equal the atomic weight. So if you know the wt. just subtract the number of protons and you will have the number of neutrons.
If you have both the mass number and atomic number you can figure it out, since the atomic number is the number of protons. Say the mass number is 13 and the atomic number is 8. 13-8 is 5, so you would have 5 neutrons.
I don't want to do your homework for you. Here's how you figure it out: Protons = atomic number Neutrons = atomic mass - atomic number Electrons = atomic number + ionization
The mass number is the total number of protons plus neutrons in the nucleus. The atomic number is the total number of protons in the nucleus. So subtract the atomic number from the mass number and that will give you the total number of neutrons in the nucleus.
atomic mass number - protons = number or neutrons
The ratio of neutrons to protons in an atom can be calculated by subtracting the atomic number (number of protons) from the atomic mass (sum of protons and neutrons) of the atom. Mathematically, ratio of neutrons to protons = (Atomic mass - Atomic number).
The Atomic Mass is equal to the number of protons plus neutrons. So if you know the atomic number then you can find out the number of neutrons Atomic # is the amount of Protons or Electrons Atomic Mass- Number of protons plus neutrons Atomic Mass-Atomic Number = Amount of neutrons
Atomic Mass: protons AND neutrons atomic number: just protons
Number of protons = Number of electrons = Atomic number Number of neutrons = Atomic number - Number of protons
The atomic mass (rounded to the nearest whole number) is the number of nucleons - i.e. protons+neutrons. The atomic number is just the number of protons. So the difference between the two (mass minus number) tells you the number of neutrons.
The mass number is the sum of the protons and neutrons, in this case 35. The atomic number is the same as he number of protons, in this case 17.