Question

give reason:
1. lithium and sodium are considered as active metals.
2. potassium is more reactive than sodium.

Answer 1

lithium and sodi are called as active elements because they are present in the most reactive group of elements which are most electropositive...
potassium is more reactive than sodium because it is present below sodium in the group and as we know electropositivity increases down the group ..

Answer 2

1.They have only one electron in their valence shell and are more active to attain a duplet in case of Lithium or octet in case of sodium.

2.Potassium is more active than sodium mainly because potassium is present below sodium in the modern periodic table.