Question

What is the daughter nucleus produced when 64Cu undergoes beta decay?

Answer 1

`""_64^30Zn` or `""_64^28Ni` depending on the type of β-decay.

Explanation:

β-decay is when either a proton decays into a neutron, releasing a positron, or a neutron decays into a proton, releasing an electron.

By looking at the periodic table, we find that copper has an atomic number of 29, so we would write copper-64 as `""_64^29Cu`.

Assuming that we are dealing with neutron decay, the mass number does not change, because protons and neutrons weigh the same, and the atomic number increases by one, as a new proton is being formed from a neutron. Because the atomic number changes, this is actually a new element: number 30, since one more proton is added to number 29.

On the periodic table, this is zinc, written as `""_64^30Zn`.

As an equation, this looks like

`""_64^29Cu -> ""_64^30Zn + ""_0^-1β`

Check that the numbers on the top and bottom add up so mass and charge are conserved.

`29 = 30 + (-1)`
`64 = 64 + 0`

If we are looking at a proton decaying into a neutron, emitting a positron, the equation would be

`""_64^29Cu -> ""_64^28Ni + ""_0^1β`