| Atomic Number: | 109 |
| Atomic Symbol: | Mt |
| Atomic Weight: | 265 |
| Electron Configuration: | -32-15-2 |
History
On August 29, 1982, physicists at the Heavy Ion Research
Laboratory, Darmstadt, West Germany made and identified element 109 by bombing a
target of Bi-209 with accelerated nuclei of Fe-58. If the combined energy of two
nuclei is sufficiently high, the repulsive forces between the nuclei can be
overcome.
In this experiment a week of target bombardment was required to produce a
single fused nucleus. The team confirmed the existence of element 109 by four
independent measurements. The newly formed atom recoiled from the target at
predicted velocity and was separated from smaller, faster nuclei by a newly
developed velocity filter. The time of flight to the detector and the striking
energy were measured and found to match predicted values.
The nucleus of 266X started to decay 5 ms after striking the detector. A
high-energy alpha particle was emitted, producing 267/107X. This in turn emitted
an alpha particle, becoming 258/105Ha, which in turn captured an electron and
became 258/104Rf. This in turn decayed into other nuclides. This experiment
demonstrated the feasibility of using fusion techniques as a method of making
new, heavy nuclei.