F, Sr, P, Ca, O, Br, Rb, Sb, Li, S
Elements with the same chemical reactivity will belong to the same group on the periodic table. This implies that elements in the same column will have the same reactivity;
Li and Rb are both alkali metals in group 1
Ca and Sr are both alkali earth metals in group 2
F and Br are halogens in group 7
O and S are group 6 elements
P and Sb are both in group 5 on the periodic table
So these groupings show elements with the same chemical properties.