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Americium |
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Pronunciation | (AM-ə-RISS-ee-əm) |
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Appearance | sillery white |
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Mass number | [243] |
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Americium in the periodic cairt |
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Eu ↑ Am ↓ (Uqs) |
plutonium ← americium → curium |
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Atomic nummer (Z) | 95 |
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Group | group n/a |
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Period | period 7 |
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Block | f-block |
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Element category | Actinide |
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Electron confeeguration | [Rn] 5f7 7s2 |
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Electrons per shell | 2, 8, 18, 32, 25, 8, 2 |
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Pheesical properties |
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Phase at STP | solit |
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Meltin pynt | 1449 K (1176 °C, 2149 °F) |
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Bylin pynt | 2880 K (2607 °C, 4725 °F) (calculatit) |
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Density (near r.t.) | 12 g/cm3 |
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Heat o fusion | 14.39 kJ/mol |
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Molar heat capacity | 62.7 J/(mol·K) |
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Vapour pressur
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
1239 |
1356 |
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Atomic properties |
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Oxidation states | +2, +3, +4, +5, +6, +7 (an amphoteric oxide) |
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Electronegativity | Pauling scale: 1.3 |
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Ionisation energies | |
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Atomic radius | empirical: 173 pm |
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Covalent radius | 180±6 pm |
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Spectral lines o americium |
Ither properties |
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Naitural occurrence | synthetic |
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Creestal structur | dooble hexagonal close packed |
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Thermal conductivity | 10 W/(m·K) |
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Electrical resistivity | 0.69 µΩ·m[1] |
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Magnetic orderin | paramagnetic |
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CAS Nummer | 7440-35-9 |
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History |
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Namin | efter the Americas |
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Diskivery | Glenn T. Seaborg, Ralph A. James, Leon O. Morgan, Albert Ghiorso (1944) |
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Main isotopes o americium |
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Isotope |
Abundance |
Hauf-life (t1/2) |
Decay mode |
Product |
241Am |
syn |
432.2 y |
SF |
– |
α |
237Np |
242mAm |
syn |
141 y |
IT |
242Am |
α |
238Np |
SF |
– |
243Am |
syn |
7370 y |
SF |
– |
α |
239Np |
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| references |