One such gap was one beneath caesium, a position later found to belong to francium. More than 40 years later, it was suggested that each element has a unique numbered position in the periodic table, ...

If the chemical symbol consists of more than one letter, any subsequent letters are lowercase. Example: Hydrogen → H, Helium → He 118 Elements and Their Symbols and Atomic Numbers ...

Estimates suggest that there is only about 30 g of francium in the whole of the ... to probe the finer details of current theories of atomic physics. In 2002, a group in the US succeeded in ...