Like in ordinary chemistry, where the same compound can be obtained by various routes, so in nuclear chemistry the same elements can be prepared artificially by means of different reactions.

   People learned to make technetium in kilogram quantities at the most wonderful factory in the world. This factory is the nuclear reactor, where energy is produced by slow neutrons splitting uranium nuclei.

The uranium nuclei break up into different fragments, each nucleus producing two fragments. These are atomic nuclei of elements situated in the centre of the Mendeleyev Table. 

   On fission uranium gives birth to elements which occupy more than 30 boxes of the Periodic Table, ranging from No.30 to No.64, and including technetium, and another of the stranger elements, which had been sought in vain for decades in the Earth's crust. This was promethium, the inhabitant of Box No.61.

Nuclear chemistry gave scientists elements heavier than uranium. Besides fragments, the fission of uranium nuclei gives rise to a large number of neutrons which can be taken up by unsplit nuclei.

   Thus it becomes possible to synthesize elements with the atomic numbers 93, 94, and so forth, known as the transuranium elements.

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