| 31. | IS there a reason why At-211 is not the longest-lived astatine isotope?
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| 32. | Neither the most stable isotope astatine-210 nor the medically useful astatine-211 occurs naturally.
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| 33. | Neither the most stable isotope astatine-210 nor the medically useful astatine-211 occurs naturally.
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| 34. | No stable or long-lived astatine isotope has been observed nor is one expected to exist.
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| 35. | It used to be known as radioactive metal that decays into astatine, radium, and radon.
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| 36. | Chemically, several anionic species of astatine are known and most of its compounds resemble those of iodine.
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| 37. | Isotopes of astatine are sometimes not listed as naturally occurring because of misconceptions or discrepancies in the literature.
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| 38. | Five elements are less frequently so classified : carbon, aluminium, selenium, polonium, and astatine.
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| 39. | Germanium forms tetrahalides with all halogens except astatine and forms dihalides with all halogens except bromine and astatine.
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| 40. | Germanium forms tetrahalides with all halogens except astatine and forms dihalides with all halogens except bromine and astatine.
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