Isotopen van fermium
Het chemisch element fermium (Fm), met een atoommassa van 257,0951 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 uur).
In de natuur komt geen fermium voor: alle isotopen zijn synthetisch bereid in een laboratorium. De eerste ontdekte synthetische isotoop was 255Fm in de fall-out van een kernproef in 1952.
De kortstlevende isotoop van fermium is 242Fm, met een halfwaardetijd van ongeveer 0,8 milliseconden. De langstlevende is 257Fm, met een halfwaardetijd van 100,5 dagen.
Overzicht
[bewerken | brontekst bewerken]| Nuclide | Z (p) | N (n) | Isotopische massa (u) | Halveringstijd | Radioactief verval | VP | Kernspin |
|---|---|---|---|---|---|---|---|
| Excitatie-energie | |||||||
| 242Fm | 100 | 142 | 242,07343(43) | 0,8(2) ms | SS | 0+ | |
| α (zelden) | 238Cf | ||||||
| 243Fm | 100 | 143 | 243,07435(23) | 210(60) ms | α (60%) | 239Cf | 7/2− |
| β+ (40%) | 243Es | ||||||
| SS (0,57%) | |||||||
| 244Fm | 100 | 144 | 244,07408(30) | 3,3(5) ms | SS (99%) | 0+ | |
| α (1%) | 240Cf | ||||||
| 245Fm | 100 | 145 | 245,07539(30) | 4,2(13) s | α (95,7%) | 241Cf | 1/2+ |
| β+ (4,2%) | 245Es | ||||||
| SS (0,13%) | |||||||
| 246Fm | 100 | 146 | 246,07530(4) | 1,1(2) s | α (85%) | 242Cf | 0+ |
| β+ (10%) | 246Es | ||||||
| β+, SS (10%) | |||||||
| SS (4,5%) | |||||||
| 247Fm | 100 | 147 | 247,07685(15) | 29(1) s | α (50%) | 243Cf | (7/2+) |
| β+ (50%) | 247Es | ||||||
| 248Fm | 100 | 148 | 248,077195(13) | 36(2) s | α (99%) | 244Cf | 0+ |
| β+ (1%) | 248Es | ||||||
| SS (0,05%) | |||||||
| 249Fm | 100 | 149 | 249,07903(11) | 2,6(7) min | β+ (85%) | 249Es | (7/2+) |
| α (15%) | 245Cf | ||||||
| 250Fm | 100 | 150 | 250,079521(13) | 30(3) min | α (90%) | 246Cf | 0+ |
| EV (10%) | 250Es | ||||||
| SS (6 × 10−4%) | |||||||
| 250mFm | 1500(300) keV | 1,8(1) s | IT | 250Fm | 7, 8 | ||
| 251Fm | 100 | 151 | 251,081575(9) | 5,30(8) uur | β+ (98,2%) | 251Es | (9/2−) |
| α (1,8%) | 247Cf | ||||||
| 251mFm | 191(2) keV | 15,2(23) µs | (5/2+) | ||||
| 252Fm | 100 | 152 | 252,082467(6) | 25,39(4) uur | α (99,99%) | 248Cf | 0+ |
| SS (0,0023%) | |||||||
| β+β+ (zelden) | 252Cf | ||||||
| 253Fm | 100 | 153 | 253,085185(4) | 3,00(12) dagen | EV (88%) | 253Es | 1/2+ |
| α (12%) | 249Cf | ||||||
| 254Fm | 100 | 154 | 254,0868542(30) | 3,240(2) uur | α (99,94%) | 250Cf | 0+ |
| SS (0,06%) | |||||||
| 255Fm | 100 | 155 | 255,089962(5) | 20,07(7) uur | α | 251Cf | 7/2+ |
| SS (2 × 10−5%) | |||||||
| 256Fm | 100 | 156 | 256,091773(8) | 157,6(13) min | SS (91,9%) | 0+ | |
| α (8,1%) | 252Cf | ||||||
| 257Fm | 100 | 157 | 257,095105(7) | 100,5(2) dagen | α (99,79%) | 253Cf | (9/2+) |
| SS (0,21%) | |||||||
| 258Fm | 100 | 158 | 258,09708(22) | 370(14) µs | SS | 0+ | |
| 259Fm | 100 | 159 | 259,1006(3) | 1,5(3) s | SS | 3/2+ | |
| 260Fm | 100 | 160 | 260,10268(54) | 1 min | 0+ | ||
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
· 
· 
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.
Cover photo is available under {{::mainImage.info.license.name || 'Unknown'}} license.
Cover photo is available under {{::mainImage.info.license.name || 'Unknown'}} license.
Credit:
(see original file).
