Answer:
The free neutron has a mass of 939,565,413.3 eV/c2, or 1.674927471×10−27 kg, or 1.00866491588 u. The neutron has a mean square radius of about 0.8×10−15 m, or 0.8 fm, and it is a spin-½ fermion.
Mass: 1.67492749804(95)×10−27 kg; 939.56542052(54) MeV/c2; 1.00866491588...
Composition: 1 up quark, 2 down quarks
Electric charge: 0 e; (−2±8)×10−22 e (experimental limits)
Magnetic polarizability: 3.7(20)×10−4 fm3