nuclear mass?

Question

is work required to pull a nucleon out of an atomic nucleus? does the necleon once outside the nucleus have more mass than it had inside the nulceus?

Answer 1

yes
no
in that order

if it didn't take work to pull a nucleon out of a nucleus, there would be no atoms. they would all spontaneously disintegrate. Similar concept in chemical reactions is energy of activation. what happens in a chemical reaction if the Ea is negative?


by nucleon I assume you mean proton or neutron. Why would a proton or neutron gain or lose mass just because it isn't in the nucleus? if you speed it up, that's a different story...

Answer 2

Depends on the nucleus and the nucleon in question. Fissile materials eject nucleons randomly and spontaneously, which lowers the total mass of the system (some of it gets converted to kinetic energy).

Answer 3

The nucleon does indeed have more mass once it has been seperated (this is known as the 'mass defect').

It requires much energy to split an atom apart...........and to extract a single nucleon is almost impossible.
Normally in fission the atom that has been split forms too similarish sized 'daughter' atoms.

Answer 4

Yes, mostly, and yes. Heavy nuclei such as uranium emit nucleons (alpha particles) spontaneously, so the work required to extract one is obviously negative.