Question #3438c

1 Answer
Mar 17, 2017


The mass of an atom, any atom is concentrated in its nucleus.


For a simple treatment of atomic structure, see [here].( But as to your question, the rest mass of an electron is #9.11xx10^-31*kg#. The rest mass of a proton (or a neutron, which also resides in the nucleus) is #1.67xx10^-27*kg#, and thus there are 3 orders of magnitude difference in terms of mass.

And thus electronic mass may be ignored given this disparity.