Achemical formula written over the arrow in a chemical equation signifies

CATALYST IS WRITTEN OVER THE ARROW IN CHEMICAL EQUATION

She will use the periodic table of elements to not only find out the chemical symbols of the elements written within the name, but also to check whether or not the elements are metals and or nonmetals, from this determine the ionic charges if needed for metals, and for metals that have more than one ionic charge, use a Roman numeral to represent the ionic charge that she would be using in writing the chemical formula of the compound.