The periodic table of elements has officially grown bigger by two new elements. These two new elements are the heaviest elements ever discovered, and are named 114 and 116. Their atomic mass is 289 and 292 respectively. To get an idea of their weight, lead has an atomic mass of 207.2. The elements are radioactive and they exist only for a number of seconds. After that, they lose all their Alpha particles.
Although we knew their existence for more than 10 years (114 was discovered in 1999 and 116 in 2000), the International Union of Pure and Applied Chemistry (IUPAC) and the International Union of Pure and Applied Physics (IUPAP) are very strict about the evidence needed for something to be added to the periodic table.
Watch the following video from Periodic Table Videos regarding this addition.