95. Americium (Am) — +3
Americium settles at +3 like most late actinides. Its everyday claim to fame is nuclear, not chemical: a speck of Am-241 (as AmO2) ionizes the air inside almost every smoke detector on Earth.
Charges of the Synthetic Elements (95–118)
Every element from americium (95) to oganesson (118) is man-made and radioactive, and none of them appears in ordinary formula problems. Rather than spreading thin facts across 24 pages, this single reference collects what is actually known — and honestly marks what is only predicted.
Rule of thumb: through lawrencium (103), the actinides mostly behave as +3 ions (with nobelium's +2 the famous exception). From rutherfordium (104) onward, each element is expected to copy the group above it — +4 like hafnium, +5 like tantalum, and so on — and the handful of single-atom experiments done so far largely agree.
Why these 24 elements share one page
Chemistry needs atoms, and these elements barely supply any. The early members (americium through einsteinium) can be made in weighable specks; beyond fermium, scientists work with counted atoms that decay in minutes, seconds, or milliseconds. “The charge of meitnerium” is not a measured fact — it is an extrapolation from group trends, and a reference site should say so plainly. Where an oxidation state below is starred as predicted, no experiment has yet confirmed it.
All 24 at a glance
| # | Element | Symbol | Common / predicted states | Chemistry status |
|---|---|---|---|---|
| 95 | Americium | Am | +3 | measured |
| 96 | Curium | Cm | +3 | measured |
| 97 | Berkelium | Bk | +3, +4 | measured |
| 98 | Californium | Cf | +3 | measured |
| 99 | Einsteinium | Es | +3 | measured |
| 100 | Fermium | Fm | +3 | measured |
| 101 | Mendelevium | Md | +2, +3 | measured |
| 102 | Nobelium | No | +2, +3 | measured |
| 103 | Lawrencium | Lr | +3 | measured |
| 104 | Rutherfordium | Rf | +4 | measured |
| 105 | Dubnium | Db | +5 | measured (single atoms) |
| 106 | Seaborgium | Sg | +6 | measured (single atoms) |
| 107 | Bohrium | Bh | +7 | measured (single atoms) |
| 108 | Hassium | Hs | +8 | measured (single atoms) |
| 109 | Meitnerium | Mt | no common simple ion | predicted only |
| 110 | Darmstadtium | Ds | no common simple ion | predicted only |
| 111 | Roentgenium | Rg | no common simple ion | predicted only |
| 112 | Copernicium | Cn | no common simple ion | predicted only |
| 113 | Nihonium | Nh | +1, +3 | predicted only |
| 114 | Flerovium | Fl | +2, +4 | predicted only |
| 115 | Moscovium | Mc | no common simple ion | predicted only |
| 116 | Livermorium | Lv | no common simple ion | predicted only |
| 117 | Tennessine | Ts | no common simple ion | predicted only |
| 118 | Oganesson | Og | no common simple ion | predicted only |
Element-by-element notes
96. Curium (Cm) — +3
Curium, named for Marie and Pierre Curie, is a straightforward +3 actinide. Gram quantities glow purple in the dark from their own decay, which limits its chemistry to remote-handled labs.
97. Berkelium (Bk) — +3, +4
Berkelium shows +3 with an accessible +4, echoing terbium above it in the lanthanide row. Milligrams of Bk-249 served as the target material for synthesizing element 117.
98. Californium (Cf) — +3
Californium is +3 in solution. Cf-252's ferocious neutron output makes it a portable neutron source for reactor start-ups, oil-well logging, and airport explosive scanners.
99. Einsteinium (Es) — +3
Einsteinium, first isolated from the debris of the 1952 hydrogen-bomb test, is a +3 actinide — and the heaviest element ever studied in a visible, weighable amount.
100. Fermium (Fm) — +3
Fermium holds the +3 actinide line, but no visible sample has ever existed: everything known about it comes from tracer experiments on billions-of-atoms scale or less.
101. Mendelevium (Md) — +2, +3
Mendelevium was the first element made and identified one atom at a time (17 atoms, 1955). It shows +3 plus an unusually accessible +2 — a preview of shell effects strengthening at the row's end.
102. Nobelium (No) — +2, +3
Nobelium breaks the actinide +3 habit: in solution it prefers +2, because losing just two electrons keeps its filled 5f14 shell intact — the ytterbium logic, amplified.
103. Lawrencium (Lr) — +3
Lawrencium closes the actinide series at +3, mirroring lutetium. Chemistry on single atoms confirmed the assignment — a triumph of one-atom-at-a-time technique.
104. Rutherfordium (Rf) — +4
Rutherfordium opens the trans-actinide d-block and behaves like a heavier hafnium: +4, confirmed by comparing how single atoms partition in chromatography against Zr and Hf standards.
105. Dubnium (Db) — +5
Dubnium tracks tantalum's +5, though single-atom experiments show quirks — occasionally it behaves more like protactinium than its group predicts, a hint of relativistic effects rearranging the script.
106. Seaborgium (Sg) — +6
Seaborgium follows tungsten at +6; gas-phase experiments produced a volatile oxychloride just as tungsten chemistry predicts. It was named for Glenn Seaborg while he was alive to see it.
107. Bohrium (Bh) — +7
Bohrium matches rhenium's +7 — its oxychloride BhO3Cl, made a few atoms at a time, sits exactly where group 7 trends extrapolate.
108. Hassium (Hs) — +8
Hassium delivered one of single-atom chemistry's best results: a volatile tetroxide, HsO4, confirming the osmium-like +8 state from just a handful of atoms.
109. Meitnerium (Mt) — no common simple ion
Meitnerium's chemistry has never been measured — atoms live milliseconds and arrive a few per week. Group position predicts iridium-like +3/+4, but that remains theory.
110. Darmstadtium (Ds) — no common simple ion
Darmstadtium is chemically unexplored; by group logic it would echo platinum's +2/+4. Its longest-lived known isotope survives about ten seconds.
111. Roentgenium (Rg) — no common simple ion
Roentgenium should be gold's heavy sibling (+3, perhaps -1 in exotic settings, calculations suggest), but no chemistry experiment has yet been possible.
112. Copernicium (Cn) — no common simple ion
Copernicium is predicted — and early adsorption experiments hint — to be startlingly volatile, possibly a liquid or gas at room temperature: mercury's inert-pair tendencies taken to the relativistic extreme.
113. Nihonium (Nh) — +1, +3
Nihonium, the first element discovered in Asia, is predicted to favor +1 — thallium's inert-pair preference deepened further. First adsorption experiments exist; firm charge chemistry does not.
114. Flerovium (Fl) — +2, +4
Flerovium is predicted at +2 with unusual volatility; some calculations once painted it nearly noble-gas-like. Experiments show it is at least less reactive than lead above it.
115. Moscovium (Mc) — no common simple ion
Moscovium's chemistry is purely predicted: a dominant +1 (not bismuth's +3), as the inert-pair effect swallows ever more electrons at the table's bottom edge.
116. Livermorium (Lv) — no common simple ion
Livermorium should show +2 (polonium's line continued), but with atoms surviving well under a second, its chemistry remains a calculation, not a measurement.
117. Tennessine (Ts) — no common simple ion
Tennessine is nominally a halogen, yet theory doubts it would ever form a -1 ion the way iodine does — relativistic effects may leave it behaving more like a metal.
118. Oganesson (Og) — no common simple ion
Oganesson ends period 7 as a 'noble gas' in name only: calculations predict a reactive semiconductor-like solid, not an inert gas. Five atoms or so exist per experiment — chemistry must wait.
Where this data comes from
States listed here follow IUPAC records and published single-atom chemistry studies; predictions follow group-trend extrapolations standard in the literature. Spotted an update we missed? Email hello@periodictablewithcharges.com — see how this site is edited.