Let's start by writing some important notes:
Proton-positive, has a mass of 1amu, atomic number.
Neutron-no charge, neutral, has a mass of 1amu.
Electron-negative, has a mass of approx 0.00054858amu.
Word bank: proton, neutron, electron, atomic number, mass number
Mostly affects the charge of the atom, not its mass---electron
Electrons have a very small mass compared to protons and neutrons.
Sum of the particles in the nucleus---mass number
The mass number is the sum of the particles in the nucleus, which are protons and neutrons. Electrons are outside the nucleus in shells or orbitals.
Always equal to the atomic number---proton
The number of protons is always equal to the atomic number of an element. Neutrons and electrons doesn't change the atomic number.
Affects only the mass of the atom, not its charge---neutron
Neutrons have the same mass compared to protons, which is 1amu. Both neutrons and protons make up the mass of an element. But because neutrons are neutral and have no charge, neutrons do not affect the charge of an atom.
Locates the atom on the periodic table---atomic number
The atomic number is the easiest way to locate elements on the periodic table. The atomic numbers increase from left to right.
Hope this helped!