Assertion: proton's mass | /r/HasProperty | negligible
Facets:
value: for many purposes
type: PURPOSE
value: practically
type: DEGREE
Source sentences:
text: The atomic mass of an atom is approximately equal to the number of protons plus the number of electrons, since the mass of electrons is practically negligible.
text: Since protons and neutrons have approximately the same mass (and the mass of the electrons is negligible for many purposes) and the mass defect of nucleon binding is always small compared to the nucleon mass, the atomic mass of any atom, when expressed in unified atomic mass units (making a quantity called the "relative isotopic mass"), is within 1% of the whole number A.
text: mass of an electron is negligible.