Sort these isotopes by whether they are most likely to undergofusion or fission.

Hydrogen-3,

Uranium-233,

Plutonium-239,

Hydrogen-1,

Helium-3,

Plutonium-241.

Atoms that most likely undergo fusion:

Hydrogen-3, Hydrogen-1, Helium-3,

Atoms that most likely undergo fission:

Uranium-233, Plutonium-239, Plutonium-241.

Explanation:

Both fusion and fission are nuclear reactions.

Fusion is the combination (union) of two nuclei into one larger nuclei, with the release of a very large energy and other subatomic particles.

Fission it the split of an atom (its nucleus) into two ore more smaller atoms, again with the release of huge amounts of energy and some subatomic particles.

The heavier atoms are unstable: they tend to split (fission) into smaller atoms to form more stable atoms. In the list of choices, uranium-233 (mass number 233), plutonium-239 (mass number 239), and plutonium-241 (mass number 241) are heavy isotopes and so they most likely undergo fission.

Only small, lighter atoms can combine their nuclei to form a larger, heavier nucleus. In the list of choices, only hydrogen-3 (mass number 3), hydrogen-1 (mass number 1), and helium-3 (mass number 3) are light enough to predict that they are the most likely to undergo fusion.