Question

Which list of radioisotopes contains an alpha emitter, a beta emitter, and a positron emitter?

(1) C-14, N-16, P-32
(2) Cs-137, Fr-220, Tc-99
(3) Kr-85, Ne-19, Rn-222
(4) Pu-239, Th-232, U-238

Answer 1

The answer is (3), they are β-, β+ and α decay mode. For (1), they are β-, β- and β- decay mode. For (2), they are β-, α and β-. For (4), they are α, α and α decay mode.

Answer 2

Answer: The correct option is 3.

Explanation: Radioisotopes which emits alpha-particle are known as alpha-emitters. These radioisotopes undergo alpha-decay.

The radioisotopes which emits beta-particle
`(_(-1)^0\beta )` are known as beta-emitters. These radioisotopes undergo beta-minus decay. In this decay a neutron gets converted to a proton and an electron.

The radioisotopes which emits positron-particle
`(_(+1)^0\beta )` are known as positron-emitters. These radioisotopes undergo beta-plus decay. In this type of decay a proton gets converted to a neutron.

From the given options,

Option 1: All the three radioisotopes undergoes beta-minus decay.

Option 2: Cs-137 and Tc-99 radioisotopes undergo beta-minus decay.

Fr-220 is a radioisotope which undergoes alpha-decay.

Option 3: Radioisotope Kr-85 undergoes beta-minus decay.

`_(36)^(85)\textrm{Kr}\rightarrow _(37)^(85)\textrm{Rb}+_(-1)^0\beta`

Radioisotope Ne-19 undergoes positron decay.

`_(10)^(19)\textrm{Ne}\rightarrow _(9)^(19)\textrm{F}+_(+1)^0\beta`

Radioisotope Rn-222 undergoes alpha decay.

`_(86)^(222)\textrm{Rn}\rightarrow _(84)^(218)\textrm{Po}+_(2)^4\alpha`

Option 4: All the three radioisotopes undergoes beta-minus decay processes.

Hence, from the above information, the correct option is 3.