Answer
(a) Zirconium (Zr)
(b) Sulfur (S)
(c) Chlorine (Cl)
(d) Radium (Ra)
Work Step by Step
(a) Elements in the same group are in the same column on the periodic table. The element that is in the same column as Ti (or titanium) is zirconium (Zr).
(b) Elements in the same group are in the same column on the periodic table. The element in this row that is in the same column as oxygen (or O) is sulfur (S).
(c) Elements in the same group are in the same column on the periodic table. The element in this row that is in the same column as fluorine (or F) is chlorine (Cl).
(d) Elements in the same group are in the same column on the periodic table. The element in this row that is in the same column as Ba (or barium) is radium (Ra).
