Looking at the same nonmetal group on the periodic table, how does the reactivity of an element in period 2 compare to the reactivity of an element in period 4?

Iam in desperate need of with this !

We are hoping to create 5.72 grams of glucose. the plant was given 4.75 liters of co2 and 2.81 g of h20. which reactant was the limiting reagent? how much excess mass did we have of the other reactant?

Is 343 in the sequence -5, -2, 1, 4, 7