Which radioisotope has an atom that emits a particle with a mass number of 0 and a charge of +1?
(1) 3h (3) 19ne
(2) 16n (4) 239pu

The correct answer is option 3.

Explanation: There are three types of particles that are emitted when a radioisotope undergo decay process:

1. Alpha particle: This particle is emitted when a radioisotope undergoes alpha decay process. The charge on the particle is +2 and mass number is 4.

2. Beta-particle: This particle is emitted when a radioisotope undergoes beta-minus decay process. The charge on the particle is -1 and mass number is 0.

3. Positron particle: This particle is emitted when a radioisotope undergoes beta-plus decay process. The charge on the particle is +1 and mass number is 0.

For the given options undergoing decay processes:

Option 1:

It emits beta-particle.

Option 2:

It emits beta-particle.

Option 3:

It emits positron-particle.

Option 4:

It emits alpha particle.

Hence, the correct option is Option 3.