Answer only C and D .
Solution:
(C) Reactivity increases from top to bottom and decreases from left to right in a modern periodic table for metals. So, the reactivity order is- Li < Na < K < Rb < Cs
(D) For nonmetals reactivity decreases on moving top to bottom. So, the increasing order of reactivity is-
I < Br < Cl < F
(C) Reactivity increases from top to bottom and decreases from left to right in a modern periodic table for metals. So, the reactivity order is- Li < Na < K < Rb < Cs
(D) For nonmetals reactivity decreases on moving top to bottom. So, the increasing order of reactivity is-
I < Br < Cl < F