Question

Write the approximate mass of a proton, neutron and electron in a.m.u.

Answer 1

Atomic mass unit (a.m.u.) is a unit of mass used to express mass of atomic particles.
One atomic mass unit (1 a.m.u.) is defined as one twelth (1/12) of the mass of an atom of carbon-12.
$1a.m.u.=1.66\times {10}^{27}kg$
(a) Mass of proton = $1.6725\times {10}^{-27}kg$
$=\frac{1.6725\times {10}^{-27}kg}{1.66\times {10}^{-27}}=1.00727a.m.u$
(b) Mass of neutron = $1.6748\times {10}^{-27}kg$
$=\frac{1.6748\times {10}^{-27}kg}{1.66\times {10}^{-27}kg}=1.00865a.m.u.$
(c) Mass of electron = $1.1091\times {10}^{-31}kg$
$=\frac{9.1091\times {10}^{-31}kg}{1.66\times {10}^{-27}kg}=0.00055a.m.u.$