Radium commonly forms Ra2+ in introductory ionic compounds.
| Element | Radium |
|---|---|
| Symbol | Ra |
| Atomic number | 88 |
| Common ionic charge | +2 |
| Common ions | Ra2+ |
Images are used as visual references; charge rules still depend on the compound.
Radium is [Rn]7s2, and both 7s electrons leave on the barium pattern. Its salts follow barium's solubility rules almost line by line (insoluble sulfate, soluble chloride) — chemistry so predictable that Marie Curie could purify it from tons of pitchblende by classical crystallization alone.
Assuming radium's glow was the radium itself. Radium paint glowed green because its radiation excited zinc sulfide phosphor mixed with it; pure radium salts self-glow faintly blue. Either way the light advertised decay — energy that was simultaneously destroying the dial-painters' jaws.
Ra2+ with SO4 2- gives RaSO4 — even less soluble than barium sulfate, the property Curie exploited to drag radium out of ore, fraction by patient fraction, in four years of crystallizations.
Radium chloride
Ra2+ balances chloride ions.
Radium oxide
Radium can form oxides where total positive and negative charge balances.
Yes — Ra-223 chloride treats prostate-cancer bone metastases: doctors deliberately harness the Ca2+ mimicry, sending an alpha emitter straight to diseased bone. The old villain's mechanism, repurposed as targeting.
Nothing safer existed: radioluminescence needed no charging and lasted years (Ra-226's half-life is 1,600 years). Chemistry knew Ra2+ was a bone-seeker only after the dial-painters fell ill — the case that founded occupational-health law.
Indirectly: Ra-226 in soil and stone decays to radon gas, which seeps indoors. Every basement radon test is, one step removed, a radium test.
Combine positive and negative ions so the total charge is zero — or let the ionic compound calculator do the crossing for you. The full chart lives on the periodic table with charges.
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