Technetium commonly forms Tc4+ Tc7+ in introductory ionic compounds.
| Element | Technetium |
|---|---|
| Symbol | Tc |
| Atomic number | 43 |
| Common ionic charge | +4, +7 |
| Common ions | Tc4+, Tc7+ |
Images are used as visual references; charge rules still depend on the compound.
Technetium is [Kr]4d5 5s2, manganese's group-mate, and copies its states: +7 with all valence electrons engaged (TcO4- parallels MnO4-) and the intermediate +4 oxide. Its chemistry was predicted by Mendeleev decades before anyone could make an atom of it.
This is a classroom reference range, not an exhaustive list of all oxidation states.
Assuming radioactivity changes charge rules. Nuclear instability lives in the nucleus; technetium's electrons follow ordinary group-7 chemistry. A pertechnetate ion behaves like a permanganate ion that happens to have an unstable core.
Four oxygens contribute -8; the ion's overall charge is -1, so Tc = +7. Hospitals inject Tc-99m in this form because the body routes pertechnetate predictably while its gamma rays map organs.
Technetium chloride
Tc4+ balances chloride ions.
Technetium oxide
Technetium can form oxides where total positive and negative charge balances.
It is 'milked' weekly from molybdenum-99 generators. Its 6-hour half-life and clean gamma emission are ideal: image, decay, gone — with the +7 pertechnetate chemistry making it easy to attach to targeting molecules.
Vanishing traces in uranium ores from spontaneous fission. Essentially every gram in existence came from reactors — the first artificial element, as its name ('technetos', artificial) records.
Still starting from +7 pertechnetate, it is reduced (often toward +4) and bound to phosphonate carriers that deposit wherever bone is actively rebuilding — lighting up fractures and lesions.
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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