Final answer:
The substances on the left side of a chemical equation are called reactants, and they are named systematically. In naming compounds, the element on the left or lower in the periodic table is usually named first, with the second element receiving an -ide suffix, while prefixes indicate the number of atoms.
Step-by-step explanation:
The substances on the left side of a chemical equation are known as reactants. These are the elements or compounds that undergo a chemical change to produce new substances. During a chemical reaction, the reactants interact and are transformed into products, which are listed on the right side of the equation. The naming of compounds is also systematic. For example, in the compound NaCl, sodium (Na) is on the left side of the periodic table and therefore is named first, and chlorIDE is the name given to the chlorine part of the compound. Ionic compounds are generally named with the metal (or positive ion) first followed by the nonmetal (or negative ion) with an -ide suffix.
When naming covalent compounds, the order of the elements is determined in a similar way. The element closer to the left or lower in the periodic table is listed first in the name. Prefixes are often used to indicate the number of atoms of each element present in the compound. For instance, in carbon tetrachlorIDE (CCl4), the 'tetra-' prefix indicates that there are four chlorine atoms.