posted by Alyssa .
What mass of electrons would be required to just neutralize the charge of 3.9 grams of protons?
The mass of one proton is 1.67 x 10^-24 grams. So 1.67 x 10^-24 g/proton x # protons = 3.9 grams.
Solve for # protons.
# electrons will be the same since the charges are the same (but opposite).
One electron has a mass of 9.11 x 10^-28 g; therefore,
9.11 x 10^-28 g x # electrons = mass of electrons.