# How big is a neutron relative to a proton?

Mar 17, 2014

A neutron is about three times the size of a proton.

#### Explanation:

The relative atomic mass of a proton is 1 and is the same for the neutron.

Therefore, a logical assumption would be that they are the same size — and that is a good approximation.

According to recent theories, a proton is a thin positive ring with radius 2 × 10^(-16) color(white)(l)"m".

A neutron is a thin positive ring with radius 2 × 10^(-16)color(white)(l) "m" inside a thin negative ring with radius 6 × 10^(-16)color(white)(l) "m".

Thus, a neutron is 3 times the size of a proton.