The strontium and the calcium ions, members of the alkaline earth series (Group IIB of the Periodic Table), have many properties in common, both having a valency of 2+, similar ionic radii, and the ability to form complexes and chelates of various solubilities and various binding strengths.
Although the preferential movement of calcium over strontium between compartments in biological systems has long been known, a primary objective of many studies in the 1950s and 1960s was to quantify the relative movement and the retention of these alkaline earth cations, and to devise procedures to minimize the body burden of radiostrontium.
Therefore, small changes in the reabsorption processes as a result of imposed variables or disease states will result in large effects on the relative urinary excretion of these alkaline earth cations.
The periodic table is color coded by classifications, such as alkali, alkaline earths
, transitions metals, metalloids, nonmetals, halogens noble gases, lanthanides and actinide, and offers 'hints' to help users name each group of elements.