The trace elements of Group 2, beryllium (Be), strontium (Sr), and barium (Ba), belong to the alkaline earths and behave similarly to Ca and Mg. Their physical properties, especially sizes of their ionic radii are fairly similar to those of Ca, and they may substitute for each other, however, the small ionic radius of Be prevents its replacement by other cations (Table 7.1). A characteristic of these cations is the small ionic radius and high charge to radius ratio. All the alkaline earths are associated with the carbon cycle that strongly controls their behavior in the environment. Be in the terrestrial environment is more susceptible to hydrolysis and complexation processes than other elements of this group.