Predicting Chemistry of the Transactinides

Velocity filter SHIP to separate transactinide fusion products from the projectile beam (reproduced with permission from G. Herrmann, An ew. Chem., Int. Ed. Engl., 1988, 27, 1422). 

Detection of these elements relies on studying their radioactive decay, which is usually either a-emission or spontaneous fission. A time-correlation process is used in this, a solid-state detector monitors both the time and position of arrival of fusion products. Subsequent decay events at this position give not just the decay information of the atom (half-life, O -particle energy) but also the corresponding information for its decay products, which are recognizable and thus known nuclei. This therefore gives a history of stepwise decay of the initial product. 

Thus reaction of ° Bi with Cr led to very short-lived nuclei h = 4.7 ms) emitting a-particles with an energy of 10.38 MeV. This a-emitter correlated with a decay chain composed of three successive a-emitters, identified as 105 (4.4 s a-particles of 9.17 MeV) Lr (13 s a-particles of 8.46 MeV) and Md (52 s a-particles of 7.75 MeV). 

The limiting factor in detecting the reaction product is thus the time of flight of the product from the target to the detector, which is of the order of microseconds. 

Elements from 104 to 112 are believed to have electron configurations resulting from filling the 6d orbitals, so they are predicted to be transition metals. For the elements with Z 112, it is assumed that the 7p orbitals are filled first elements 119 and 120 involve filling the 8s orbital whilst from 121 to 153, one electron is first placed in the 7d (or 8p) orbital 

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