Scientist have grouped the number of elements into

columns and rows on the periodic table and groups based on reactivity and such like halogens,noble gases, trans metals, alkali metals, alkaline earth metals, lanthanids, actinids, metalliods, nonmetals and metals.

Explanation:

447.63 g HClO₃

Explanation:Moles are calculated by dividing the mass of a compound by its relative formula mass.Therefore, when given the number of moles, to get the mass of the compound we multiply the number moles by the relative formula mass of the compound.Relative formula mass i given by adding the atomic masses of elements present in the compound.

In this case;

Relative formula mass of HClO₃ = 84.459 g

We are given, Moles of HClO₃ = 5.3 moles

Therefore;

Mass of HClO₃ = 5.3 moles × 84.459 g/mol

                        = 447.6327 g

                       = 447.63 g (2 d.p.)

Thus, the mass of HClO₃ in 5.3 moles is 447.63 g