Investigating the heaviest elements known is rewriting our knowledge of chemistry and may even mean the end of the periodic table itself, writes Kit Chapman.
In 2018, Peter Schwerdtfeger published a paper that turned chemistry on its head. According to calculations he and his colleagues performed, oganesson – element 118, the heaviest known – was not a noble gas as you would expect from its position in the periodic table, but a highly reactive solid. Even stranger, it didn’t seem to have electron shells.1
‘Well, that statement is oversimplified,’ says Schwerdtfeger, a theoretical chemist at Massey University in New Zealand. ‘You can still build up the electron densities from orbitals describing individual shells. What happens is that for oganesson the shell structure is barely visible, approaching an electron gas.’