Group 2A of the Periodic table contains the Alkaline Earth matals. Those elements are: Beryllium ( Be ), Magnesium ( Mg ), Calcium ( Ca ), Strontium ( Sr ), Barium ( Ba ) and Radium ( Ra ). Beryllium is the lightest member of the group 2A. Ionic radius increases moving down the group ans decreases from left to right across the period of elements. In the group 2A ionic radius increases from Beryllium ( 59 pm - picometers ) to Radium ( 163 pm ). Answer: Beryllium has the lowers ionic radius.
