What isotope would be produced by the positron decay of bismuth-210?

Question

im not sure how to figure this out i have between mercury-207, lead-210, polonium-210, thallium-206....im not sure out out 4 is the answer and why...can anyone explain...thanks

Answer 1

The postitron decay of bismuth-210 will result in lead-210.

Positron decay is like a mirror image of beta decay. A simplified view of what positron decay actually is:

1) Something inside the nucleus of an atom breaks down, which causes a proton to become a neutron.
2) It emits a positron and a neutrino which go zooming off into space.
3) The atomic number goes DOWN by one and mass number remains unchanged.

I hope this helps.

Answer 2

Bismuth-210 undergoes *beta* decay. This can be thought of as losing an electron from the nucleus. Therefore a neutron becomes a proton. The atomic mass is virtually unchanged, but the atomic number goes up by one.

Bi-210 --> Po-210. + e- (T1/2 ~~ 5 days)

Polonium will then emit an alpha particle to become lead.

Po-210 --> Pb206 + He2+ (T1/2 ~ 138 days)

However Bi-207 and Bi-208 both undergo positron emission to become Pb207 and Pb208 repectively.

Answer 3

bismuth 210 has Z=83 and M=210

When a positron is emitted M does not change so ramains 210,

but a charge + is lost and a proton transforms in neutron giving Z=82

So ,you obtain Pb 210