I need help solving this problem:

Choose from the list below three pairs of elements that will form molecular compounds. (An element may be chosen more than once. Select all that apply.)

iodine (I) cadmium (Cd) bromine (Br) barium (Ba) phosphorus (P) rubidium (Rb)

iodine (I) and phosphorus (P)

cadmium (Cd) and iodine (I)

iodine (I) and bromine (Br)

cadmium (Cd) and barium (Ba)

barium (Ba) and rubidium (Rb)

rubidium (Rb) and phosphorus (P)

barium (Ba) and bromine (Br)

cadmium (Cd) and rubidium (Rb)

bromine (Br) and phosphorus (P)