(a) Name two elements you would expect to show chemical reactions similar to sodium.
What is the basis of your choice?
(b) Arrange the elements present in that group in the increasing order of reactivity.
Give reason.

Explanation

(a) Lithium and potassium show same chemical properties as sodium, because all the three
elements possess same number of valence electrons and belong to same group, that is, IA
group.
(b) Increasing order of reactivity is "LiltNaltKltRbltCs." This is due to decrease in ionisation
potential values from top to bottom in a group.