Mendeleev's predicted elements
Other scientists use the eka- prefix, too. Eka- is also used in the names of elements that Mendeleev did not predict. Before francium was discovered, it was called eka-caesium, and before astatine was discovered, it was called eka-iodine. The eka- prefix is also used to name transuranic elements (elements after uranium). For example, ununoctium is also called eka-radon, and untriennium (element number 139) is also called eka-actinium. Today, the IUPAC uses the systematic element name to give new elements a temporary name. This new way of naming elements depends on the atomic number of the element. It does not depend on the position of the element in the periodic table.