what group and period does Barium (Ba) belong?
a
Grroup 137, Period 56
b
Group 6, Period 2
c
Group 56, Period 137
d
Group 2, Period 6
d
Group 2, Period 6
a
Grroup 137, Period 56
b
Group 6, Period 2
c
Group 56, Period 137
d
Group 2, Period 6
Group 2, Period 6