Match the nuclear reaction to its description.

Column A
1. Forms two lighter nucleus
2. Forms one heavier nucleus
3. Has been successfully used to generate energy
4. Has NOT been successfully used to generate energy/electricity

Column B.
A. Fusion
B. Fission

1. B. Fission

2. A. Fusion
3. B. Fission
4. A. Fusion

Column A

1. B. Fission
2. A. Fusion
3. A. Fusion
4. B. Fission

To match the nuclear reactions to their descriptions, we need to understand the processes of fusion and fission.

1. Forms two lighter nucleus: This refers to the process of fusion. In fusion, two smaller atomic nuclei come together to form a larger, more massive nucleus. This reaction usually occurs at extremely high temperatures and pressures, as in the core of the Sun. The correct match is A. Fusion.

2. Forms one heavier nucleus: This describes the process of fission. In fission, a heavy nucleus is split into two or more smaller nuclei, releasing a significant amount of energy. This reaction is commonly used in nuclear power plants and atomic bombs. The correct match is B. Fission.

3. Has been successfully used to generate energy: This matches with fission. Nuclear power plants use controlled fission reactions to generate electricity. The large amount of energy released in these reactions can be harnessed for various purposes.

4. Has NOT been successfully used to generate energy/electricity: This matches with fusion. Despite considerable efforts, fusion has not yet been effectively harnessed to generate electricity on a large scale. Scientists are still striving to achieve controlled fusion reactions that can be used for practical energy production.

So, the matching would be:
1 - A. Fusion
2 - B. Fission
3 - B. Fission
4 - A. Fusion