Final answer:
The mass of a neutron is slightly greater than the mass of a proton.
Step-by-step explanation:
A proton and a neutron have almost the same mass. However, a proton is slightly lighter than a neutron. The mass of a proton is approximately 1.007 atomic mass units (amu), while the mass of a neutron is approximately 1.008 amu. So, a neutron has more mass than a proton.
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