Recent studies of nuclear and chemical properties of elements 103, 104 and 105

Results of recent experiments to determine the chemical and nuclear properties of element 103 (the last of the actinides) and elements 104 and 105, the beginning of the transactinides, will be discussed. Comparison of even rudimentary chemical behavior (such as the most stable oxidation states and complexing ability) of these elements with their lighter homologs is important in establishing the validity of predictions based on extrapolation of trends shown in a given family of the periodic table. Knowledge of the chemical behavior is also important in assessing the influence of relativistic effects in these very heavy elements. Information about their nuclear properties is essential for these studies. The known isotopes of elements 104 and 105 are all very short-lived, can only be produced an atom-at-a-time at an appropriate accelerator, and must be identified by measurement of their radioactivities. Some of the difficulties involved in the studies and the unique facilities and capabilities which are required will be discussed