Matter is what occupies space and possesses rest mass, especially as distinct from energy. Pure Substance is a material consisting of one particular kind of matter. Element is the simplest form of matter which cannot be decomposed by ordinary chemical means. Metals are substances with lustrous or shiny appearance and are malleable (can be hammered into thin sheets), ductile (can be drawn into wires), and good conductors of heat and electricity. Nonmetals are substances with dull appearance and are brittle (can easily be broken into pieces like charcoal, and poor conductors of heat and electricity). Metalloids or amphoteric are substances which act either as metals or nonmetals. Compound is chemical combination of two or more elements which can be further decomposed by ordinary chemical means. Organic is any of a large class of chemical compounds in which one or more atoms of carbon are covalently linked to atoms of other elements, most commonly hydrogen, oxygen, or nitrogen. Inorganic compound is a substance that does not contain both carbon and hydrogen