‘Modern alchemy: from missing elements to synthetic elements’ explores the science behind the synthesis of elements. Rutherford and Soddy were able to transmute elements by bombarding nuclei with particles. This only worked up to calcium, and it took the invention of the cyclotron in the 1930s to enable the transmutation of heavier elements. This enabled the gaps in the periodic table to be filled. The twenty-six elements after uranium in the periodic table do not always follow periodicity, so they were excised from the main body and put into their own section. The high speeds of electrons in atoms can produce relativistic effects, but the chemical periodicity of elements is a remarkably robust phenomenon.