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.