# Proton and neutron

isn't a neutron more massive thatn a proton?

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It is. Free neutrons are even unstable and decay with a lifetime of something like 12min. To my big surprise, when I looked it up, the mass-difference was much more than I expected: 2.5 times the mass of an electron (I expected not much more than the electron mass).

The neutron is about 0.2% more massive than a proton, which translates to an energy difference of 1.29 MeV. I believe that the added mass of the electron plus the proton equals very close to the mass of the neutron.

Atheist said:
It is. Free neutrons are even unstable and decay with a lifetime of something like 12min. To my big surprise, when I looked it up, the mass-difference was much more than I expected: 2.5 times the mass of an electron (I expected not much more than the electron mass).
This is impossible, the mass of the proton is 1.67262158 × 10-27 kilograms, while the mass of the electron is 9.10938188 × 10-31 kilograms. This means that the proton has a mass more than 10^4 times that of the electron.

How come when a proton turns into a neutron (as in nuclear fusion in the Sun) it gives out energy AND gains in mass, where does all the extra energy come from

Masses given for particles are the masses of free particles. When particles bond together the created particle can have a lower mass than the sum of the constituents (to some extend one can even see this as the reason why stable bound states exist). The mass-difference is called the bonding energy.

@ArmoSkater: You seem to have mistaken my 1st post.

ArmoSkater87 said:
This is impossible, the mass of the proton is 1.67262158 × 10-27 kilograms, while the mass of the electron is 9.10938188 × 10-31 kilograms. This means that the proton has a mass more than 10^4 times that of the electron.
I think he means that he thought the difference in mass between a neutron and a proton would be close to the mass of an electron.

What, the *** are you guys talking about ???

regards
marlon

They are trying to make us swallow that a neutron = a proton + an electron :tongue2:

Based upon what evidence ???

What is the underlying theory here ...

regards
marlon

That would simply be wrong.