How do you figure out the number of electrons, neutrons, and protons of an element by only being given the mass?

Well there is the same amount of electrons as protons and if you add the number of protons and neutrons together you get the atomic number.

the number of protons is roughly half that of the atomic number but not all the time so i dont know how to find it just from the atomic mass but if you have a periodic table you can look at the atomic mass and find which element it is and then do it from there also the atomic mass is the bottom numbers the protons are the top numbers of the atom in like 2

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Get a periodic table of elements ... Find your element on the periodic table ... Locate the element's atomic number ... Determine the number of electrons ... Look for the atomic mass of the element ... Subtract the atomic number from the atomic mass.