Isotopen van americium
Het chemisch element americium (Am), met een atoommassa van 237,0482 u, bezit geen stabiele isotopen en wordt dus geclassificeerd als radioactief element. De 18 radio-isotopen zijn onstabiel en hebben een relatief korte halfwaardetijd (de meeste minder dan een minuut).
In de natuur komt geen americium voor: alle isotopen zijn synthetisch bereid in een laboratorium. De eerste synthetische isotoop was 241Am, in 1944.
De kortstlevende isotoop van americium is 225Am, met een halfwaardetijd van ongeveer 3 milliseconden. De langstlevende is 243Am, met een halfwaardetijd van 7370 jaar.
Overzicht
[bewerken | brontekst bewerken]| Nuclide | Z (p) | N (n) | Isotopische massa (u) | Halveringstijd | Radioactief verval | VP | Kernspin |
|---|---|---|---|---|---|---|---|
| Excitatie-energie | |||||||
| 231Am | 95 | 136 | 231,04556(32) | 30 s | β+ | 231Pu | |
| α (zelden) | 227Np | ||||||
| 232Am | 95 | 137 | 232,04659(32) | 79(2) s | β+ (98%) | 232Pu | |
| α (2%) | 228Np | ||||||
| β+, SS (0,069%) | |||||||
| 233Am | 95 | 138 | 233,04635(11) | 3,2(8) min | β+ | 233Pu | |
| α | 229Np | ||||||
| 234Am | 95 | 139 | 234,04781(22) | 2,32(8) min | β+ (99,95%) | 234Pu | |
| α (0,04%) | 230Np | ||||||
| β+, SS (0,0066%) | |||||||
| 235Am | 95 | 140 | 235,04795(13) | 9,9(5) min | β+ | 235Pu | 5/2− |
| α (zelden) | 231Np | ||||||
| 236Am | 95 | 141 | 236,04958(11) | 3,6(1) min | β+ | 236Pu | |
| α | 232Np | ||||||
| 237Am | 95 | 142 | 237,05000(6) | 73,0(10) min | β+ (99,97%) | 237Pu | 5/2− |
| α (0,025%) | 233Np | ||||||
| 238Am | 95 | 143 | 238,05198(5) | 98(2) min | β+ | 238Pu | 1+ |
| α (10−4%) | 234Np | ||||||
| 238mAm | 2500(200) keV | 35(10) µs | |||||
| 239Am | 95 | 144 | 239,0530245(26) | 11,9(1) uur | EV (99,99%) | 236Pu | 5/2− |
| α (0,01%) | 235Np | ||||||
| 239mAm | 2500(200) keV | 163(12) ns | (7/2+) | ||||
| 240Am | 95 | 145 | 240,055300(15) | 50,8(3) uur | β+ | 240Pu | (3−) |
| α (1,9 × 10−4%) | 236Np | ||||||
| 241Am | 95 | 146 | 241,0568291(20) | 432,2(7) jaar | α | 237Np | 5/2− |
| CV (7,4 × 10−10%) | 207Tl, 34Si | ||||||
| SS (4,3 × 10−10%) | |||||||
| 241mAm | 2200(100) keV | 1,2(3) µs | |||||
| 242Am | 95 | 147 | 242,0595492(20) | 16,02(2) uur | β− (82,7%) | 242Cm | 1− |
| EV (17,3%) | 242Pu | ||||||
| 242m1Am | 48,60(5) keV | 141(2) jaar | IT (99,54%) | 242Am | 5− | ||
| α (0,46%) | 238Np | ||||||
| SS (1,5 × 10−8%) | |||||||
| 242m2Am | 2200(80) keV | 14,0(10) ms | (2+, 3−) | ||||
| 243Am | 95 | 148 | 243,0613811(25) | 7,370(40) jaar | α | 239Np | 5/2− |
| SS (3,7 × 10−9%) | |||||||
| 244Am | 95 | 149 | 244,0642848(22) | 10,1(1) uur | β− | 244Cm | (6−) |
| 244mAm | 86,1(10) keV | 26(1) min | β− (99,96%) | 244Cm | 1+ | ||
| EV (0,0361%) | 244Pu | ||||||
| 245Am | 95 | 150 | 245,066452(4) | 2,05(1) uur | β− | 245Cm | 5/2+ |
| 246Am | 95 | 151 | 246,069775(20) | 39(3) min | β− | 246Cm | (7−) |
| 246m1Am | 30(10) keV | 25,0(2) min | β− (99,99%) | 246Cm | 2− | ||
| IT (0,01%) | 246Am | ||||||
| 246m2Am | ± 2000 keV | 73(10) µs | |||||
| 247Am | 95 | 152 | 247,07209(11) | 23,0(13) min | β− | 247Cm | (5/2) |
| 248Am | 95 | 153 | 248,07575(22) | 3 min | β− | 248Cm | |
| 249Am | 95 | 154 | 249,07848(32) | 1 min | β− | 249Cm | |
Overzicht van isotopen per element
[bewerken | brontekst bewerken]| 1 | 18 | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | H | 2 | Periodiek systeem | 13 | 14 | 15 | 16 | 17 | He | |||||||||
| 2 | Li | Be | De links verwijzen naar isotopen per element | B | C | N | O | F | Ne | |||||||||
| 3 | Na | Mg | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | Al | Si | P | S | Cl | Ar |
| 4 | K | Ca | Sc | Ti | V | Cr | Mn | Fe | Co | Ni | Cu | Zn | Ga | Ge | As | Se | Br | Kr |
| 5 | Rb | Sr | Y | Zr | Nb | Mo | Tc | Ru | Rh | Pd | Ag | Cd | In | Sn | Sb | Te | I | Xe |
| 6 | Cs | Ba | ↓ | Hf | Ta | W | Re | Os | Ir | Pt | Au | Hg | Tl | Pb | Bi | Po | At | Rn |
| 7 | Fr | Ra | ↓↓ | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og |
| Lanthaniden | La | Ce | Pr | Nd | Pm | Sm | Eu | Gd | Tb | Dy | Ho | Er | Tm | Yb | Lu | |||
| Actiniden | Ac | Th | Pa | U | Np | Pu | Am | Cm | Bk | Cf | Es | Fm | Md | No | Lr | |||
Bronnen, noten en/of referenties
- (en) R.B. Firestone, S.Y. Frank Chu & C.M. Baglin (1999) - Table of Isotopes (online versie van de cd-rom)
- (en) G. Audi, A.H. Wapstra, C. Thibault, J. Blachot & O. Bersillon (2003) - The NUBASE evaluation of nuclear and decay properties, Nuclear Physics A, 729, pp. 3-128
- (en) J.R. de Laeter, J.K. Böhlke, P. De Bièvre, H. Hidaka, H.S. Peiser, K.J.R. Rosman & P.D.P. Taylor (2003) - Atomic weights of the elements. Review 2000 (IUPAC Technical Report), Pure and Applied Chemistry, 75 (6), pp. 683–800
- (en) M.E. Wieser (2006) - Atomic weights of the elements 2005 (IUPAC Technical Report), Pure and Applied Chemistry, 78 (11), pp. 2051–2066
- (en) David R. Lide (2004) - CRC Handbook of Chemistry and Physics (85th ed.), hoofdstuk 11, CRC Press - ISBN 978-0849304859
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