| 41. | The least stable ground state isotope is astatine-213, with a half-life of 125 nanoseconds.
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| 42. | It was formerly known as "'radioactive metal that decays into astatine, radium, and radon.
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| 43. | Lighter astatine isotopes have quite high energies of alpha decay, which become lower as the nuclei become heavier.
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| 44. | She became provisional director of the institute in 1945 and official in 1947 upon discovering the existence of astatine.
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| 45. | The electron affinity of astatine is predicted to be reduced by one-third because of spin-orbit interactions.
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| 46. | The most stable isotope is astatine-210, which has a half-life of 8.1 hours.
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| 47. | Francium-221 then decays into astatine-217 by alpha decay ( 6.457 MeV decay energy ).
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| 48. | There are 32 known isotopes of astatine, with atomic masses ( mass numbers ) of 191 and 193 223.
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| 49. | No stable or even long-lived astatine isotope is known, and no such isotope is expected to exist.
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| 50. | The least stable ground state isotope is astatine-213, with a half-life of about 125 nanoseconds.
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