Answer:
a. Chemical formula
Explanation:
A notation that shows which elements, and how many of each type a compound contains is a chemical formula.
Basically, a chemical formula helps scientists to show or illustrate the type and number of atoms present in a particular molecule or compound by using numerical subscript, ions and atomic symbol of a chemical element.
This ultimately implies that, a chemical formula is used to describe or denote the exact amount of atoms that make up a molecule or compound.
Some examples of a chemical formula are;
Water = [tex]H_{2}O[/tex]
Sodium Hydroxide = [tex]NaOH[/tex]
Hydrochloric acid = [tex]HCl[/tex]
Carbon II oxide = [tex]CO_{2}[/tex]
