Question

The mass of a neutron in atomic mass units is:

Options

• \[1.00866~\mathrm{u}\]

• \[1.0078~\mathrm{u}\]

• \[1.660539~\mathrm{u}\]

• \[1.00727~\mathrm{u}\]

Answer 1

The mass of a neutron is \[m_n = 1.00866~\mathrm{u} = 1.6749 \times 10^{-27}~\mathrm{kg}\]. This is very nearly equal to the proton mass of \[1.00727~\mathrm{u}\], consistent with the definition of the neutron as a neutral particle of nearly the same mass as a proton.