The most reactive metal in group three

Actinium is the most reactive element or metal in group 3.

Explanation:

Reactivity of an element or metal is defined as its tendency to loose or gain atoms. Group 3 elements consist of metal. We know that reactivity of metal increases as we go down to the bottom of the column.

group 3 metals have 3 electrons in valence shell. They react by loosing 3 electrons. it has oxidation state of +3 and are electropositive.

Group 3 consists of scandium, yttrium, lanthanum and actinium.

Actinium is called actinide.

since electrons are negative the answer is neagtaive