1887-1975

Polish-American chemist who helped to formulate the radioactive displacement law. This law states that when a radioactive atom emits an alpha particle (two protons and two neutrons), its atomic number decreases by two. By contrast, when an atom emits a beta particle (an electron), its atomic number increases by one. In addition, Fajans developed rules that describe the conditions under which covalent bonding is more likely to occur than ionic bonding, and vice versa.