Abstract
Chemistry is the science that deals with the composition and properties of matter. Properties of matter are generally grouped into two broad categories; these are physical and chemical properties. Physical property is the one that a sample of matter displays without changing its composition. The physical and chemical properties of a substance depend on its size and the arrangement of elements in the chemical compound. Considering physical and chemical properties of matter, it is demanded that the difference between atom and chemical element, chemical compound and substance concepts demand that we distinguish them. In this paper, these concepts are considered on microscopic and macroscopic levels.