[s3a]

Do all individual electrons regardless of which atom or element have the same exact mass (9.109*10^(-31) kg) or is that just for the hydrogen atom's electron?

Any input would be greatly appreciated!
Thanks in advance!

[renge ishyo]

As far as we know all electrons do have the same mass. There are some curious subatomic particles called muons which are often labeled as "heavy electrons" because most of their physical and chemical properties (with the exception of mass) are identical to the electron. You can even have muons substitute for electrons in the orbits of atoms...temporarily. The muon quickly decays to a normal electron and releases a few other subatomic particles in the process.