Lithium, sodium and potassium formed a group called alkali metal group. Their similar properties are:
(i) All these elements are metals.
(ii) All these react readily with water to form alkalies and hydrogen gas.
(iii) All of them have a valency of 1.
Consider the following elements:
K, I, Li, Sr, CI, Mg, Br, Ca, Na.
Separate these elements in three groups or triads having similar properties. State one property in each case on the basis of which groups are separated.
