* Systematic names are used for reported elements until an official name has been accepted.

Atomic masses are averages based upon the naturally occurring composition of isotopes on Earth. For elements that have slightly different isotopic composition depending on the source, IUPAC now reports a range of values for atomic masses. These atomic masses are shown here in bold italics. The atomic masses in this table have been rounded to values sufficiently accurate for everyday calculations. Per IUPAC convention, no values are listed for elements whose isotopes lack a characteristic abundance in natural samples.

The discoveries of elements with atomic numbers 113, 115, and 117 -118 have been reported but not fully confirmed.