Answer:
b. group number.
Explanation:
The alkali metals are located in group 1 of the periodic table and are the following: lithium, sodium, potassium, rubidium, cesium and francium and form ions with a positive charge because they are in group 1 of the periodic table .
The alkaline earth metals are located in group 2 of the periodic table and are the following: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radius (Ra) and form ions with two positive charges because they are in group 2 of the periodic table.
The aluminum is embedded within the set of other metals and belongs to group 3A and therefore can form an ion with 3 positive charges.