# Calculate the binding energy

1. May 1, 2013

### JMP1961

Last edited: May 1, 2013
2. May 2, 2013

### Simon Bridge

Where could they be?
If the only thing that has happened is the ejection of a He nucleus from the radium nucleus then, logically, what happened to the electrons?

Generally the atomic binding energies of the electrons are so small compared with the nuclear energies that we don't bother to include them.

3. May 2, 2013

### Staff: Mentor

The masses that you find in tables are always atomic masses (including enough electrons to make a neutral atom), not nuclear masses. The mass that you give for an alpha particle is actually for a neutral helium atom, so it includes the mass of two electrons.

For a nuclear decay, strictly speaking you should use nuclear masses when calculating the energy released, but it's OK to use atomic masses in alpha decay because the total number of "extra" electron masses is the same before and after so they cancel out. With beta+ and beta- decay you have to be more careful.

4. May 5, 2013

### Phenylflux

I remember alphas as the worst type of ionizing radiation because of the net positive charge. The 2 He 4 with a +2 charge. An alpha is so ionizing it can't make it through a sheet of paper. So it would reason that after the decay the ejected alpha would quickly strip the electrons from somewhere.

5. May 5, 2013

### Simon Bridge

@JMP1961: any of this of any use?

6. May 5, 2013

Staff Emeritus
The OP hasn't been here since he posted that question.

7. May 5, 2013

### Simon Bridge

Has OP turned on email notifications?