(02)Stable + Unstable Nuclei

Binds nucleons together.

Stronger attractive force than the electrostatic is repulsive at short distances (0.5fm<d<3fm)

Works equally between nucleons

At very small separations is repulsive (<0.5fm)

Strong nuclear force

1fm = 1×10^-15m (1/000 of a nanometer)

m to fm

Only happens in very large nuclei - there needs to be enough nucleons that the strong force can’t hold all of them from repelling each other.

2p + 2n (helium nucleus)

Very short range -only a few cm- in air.

Can be seen by observing tracks in a cloud chamber or detected on a Geiger counter.

Alpha emission (α)

Beta minus decay (β-minus) is the emission of an electron from the nucleus along with an antineutrino.

Occurs in isotopes which are neutron-rich

Re → Os + β + antineutrino

Beta emission (β)

I’m 1930 Wolfgang Pauli suggested another particle was being emitted along with the electron as the energy didn’t balance. 25 years later the antineutrino was observed.

Theorisation of antineutrino