In the prosperous 2 1 century, it is not impossible to transform one chemical element into another by artificial methods. This is not only because scientists know that atoms are made up of nuclei and electrons, and nuclei are made up of protons and neutrons, but also because they have mastered weapons powerful enough to knock down the doors of proton nuclei, split atoms and recombine them into new atoms. It was British chemist and physicist Rutherford who laid the theoretical and experimental foundation for this research work.

In 19 10, Rutherford carried out the famous experiment of alpha particles bombarding gold foil. He found that most alpha particles can move on through the gold foil, and some alpha particles have changed their original direction, but the change angle is not big. Only a few alpha particles will bounce back, as if they hit a hard and impenetrable object.

Rutherford believes that this experiment shows that there is a small nucleus in the gold atom, and the mass and positive charge of the atom are concentrated in the nucleus. When the alpha particle passes through the space part of the atom, it can pass smoothly without resistance, but if it touches the nucleus, it will repel each other (both the alpha particle and the nucleus are positively charged) and the alpha particle will bounce back.

Rutherford imagined that there were 79 protons and 1 18 neutrons in the gold core, which was too heavy, and the repulsive force between alpha particles and the gold core was too great to blow away the gold core. If two measures are taken: on the one hand, bombarding with high-energy alpha particles; On the other hand, the bombarded objects are changed into light nuclei, such as nitrogen nuclei (containing 7 protons and 7 neutrons). Then, the repulsive force between alpha particles and nitrogen nuclei is much smaller, and perhaps high-energy alpha particles may blow away the nitrogen nuclei.

The result of the experiment is really like Rutherford's idea. After the alpha particle enters the nitrogen nucleus, two protons and two neutrons in the alpha particle recombine with seven protons and seven neutrons in the nitrogen nucleus to form a hydrogen atom and an oxygen atom.

After the nucleus of one atom is exploded, it becomes two other atoms, which means that chemists can synthesize chemical elements artificially. Rutherford's discovery has also changed the theory that "elements will never change" in the chemical field since19th century. Indeed, the exploration of this scientist who won the Nobel Prize in Chemistry in 1908 is groundbreaking.

Although Rutherford got some light elements after splitting atoms, it is also possible to get heavy elements by artificial methods. As long as we can build a more powerful "cannon" and emit all kinds of high-energy particles, we can achieve our goal. 1929, Lawrence, a professor of physics at the University of California, designed a cyclotron. The speed of accelerating charged particles is close to the speed of light and has extremely high energy.

Starting from 1940, American chemists Seeburg and Macmillan bombarded targets made of different elements with high-energy particles produced by cyclotron, and successively made nine artificial elements such as americium and curium by artificial methods. Up to now, elements 95 to 1 12 discovered by scientists all over the world are all made during nuclear reaction.