Final answer:
To classify a substance, it is identified as an atomic element, molecular element, molecular compound, or ionic compound, based on its composition and the types of bonds that hold it together.
Step-by-step explanation:
To provide the classification of a substance, one must evaluate whether it is an atomic element, a molecular element, a molecular compound, or an ionic compound. An atomic element consists of single atoms as their basic units. A molecular element contains two or more atoms of the same element bonded together. A molecular compound is formed from molecules containing two or more different elements that are covalently bonded, and an ionic compound is composed of positively and negatively charged ions held together by ionic bonds. Using the periodic table, one can identify elements and predict the type of substance they form based on their group and period.