Lorenzo is making a prediction. “i learned that nonmetals increase in reactivity when moving from left to right. so i predict that xenon will be more reactive than iodine.” is lorenzo correct? if so, why? if not, explain his error.

No, he is not correct. Xenon is not very reactive since it is located in the group of noble gases. The noble gases are all chemically unreactive gases.Elements within different groups within the periodic table have different physical and chemical properties. Hope this answers the question.

Molarity is moles of solute over liters of solution. idk if that is what you are talking about, but you can convert moles of solute to grams of solute using dimensional analyzes by using molar mass found on the periodic table.