Without looking at the periodic table, select the elements belonging to same group from the following list.
Z = 12,38, 56
Z = 9, 16,3,35
Z = 5, 11, 27 , 19
Z = 24, 47 , 42, 55
Group 2. Li (Z = 4), Mg (Z = 12), Ca (Z = 20), Sr (Z = 38), Ba (Z = 56), Ra (Z = 88)