Synthetic elements

Tc Technetium Transition metal · Z 43 · 98 u The first element made by humans rather than found — and the lightest with no stable isotope at all. Pm Promethium Lanthanide · Z 61 · 145 u The only lanthanide with no stable isotope — it decayed away and had to be made in a reactor. Am Americium Actinide · Z 95 · 243 u The element quietly sitting in millions of smoke detectors worldwide. Cm Curium Actinide · Z 96 · 247 u Named for the Curies, and the isotope that has analysed the soil of Mars. Bk Berkelium Actinide · Z 97 · 247 u Made in milligram quantities and used mainly as a target for creating even heavier elements. Cf Californium Actinide · Z 98 · 251 u A neutron source strong enough to be used in oil-well logging and cancer treatment. Es Einsteinium Actinide · Z 99 · 252 u Discovered in the fallout of the first hydrogen bomb test, in samples flown through the cloud. Fm Fermium Actinide · Z 100 · 257 u The heaviest element that can be made in weighable amounts by neutron bombardment. Md Mendelevium Actinide · Z 101 · 258 u The first element produced and identified one atom at a time. No Nobelium Actinide · Z 102 · 259 u The subject of a decade-long discovery dispute between Swedish, American and Soviet teams. Lr Lawrencium Actinide · Z 103 · 262 u The last actinide, with an electron configuration that broke the expected pattern. Rf Rutherfordium Transition metal · Z 104 · 267 u The first transactinide — and chemically a heavier cousin of hafnium, not an actinide at all. Db Dubnium Transition metal · Z 105 · 268 u Named after Dubna, the Russian town where much of superheavy chemistry was pioneered. Sg Seaborgium Transition metal · Z 106 · 271 u Named for Glenn Seaborg while he was still alive — a first for the periodic table. Bh Bohrium Transition metal · Z 107 · 272 u A superheavy element whose chemistry, tested one atom at a time, behaves as predicted for group 7. Hs Hassium Transition metal · Z 108 · 270 u One of the heaviest elements whose chemistry has been tested, one atom at a time. Mt Meitnerium Transition metal · Z 109 · 276 u Named for Lise Meitner, who explained nuclear fission but was left off the Nobel Prize. Ds Darmstadtium Transition metal · Z 110 · 281 u Created at Darmstadt in 1994 by fusing nickel and lead nuclei. Rg Roentgenium Transition metal · Z 111 · 280 u Named for the discoverer of X-rays, and predicted to be chemically like gold. Cn Copernicium Transition metal · Z 112 · 285 u Predicted to be a volatile liquid — a metal that behaves almost like a noble gas. Nh Nihonium Post-transition metal · Z 113 · 284 u The first element discovered and named by an Asian research team. Fl Flerovium Post-transition metal · Z 114 · 289 u Predicted to sit in an "island of stability" where superheavy nuclei live far longer. Mc Moscovium Post-transition metal · Z 115 · 288 u Its decay chain provided crucial confirming evidence for the discovery of nihonium. Lv Livermorium Post-transition metal · Z 116 · 293 u Made by fusing calcium-48 with curium-248, and decays within milliseconds. Ts Tennessine Halogen · Z 117 · 294 u The second-to-last gap in the seventh period, filled in 2010 with a berkelium target. Og Oganesson Noble gas · Z 118 · 294 u The heaviest element yet made, and one of only two named after a person who was alive at the time (the other is seaborgium).