Metals are materials characterized by its physical and chemical properties, primarily its ability to conduct electricity and heat, its luster or shine when polished, its malleability (ability to be hammered or pressed into shapes), and its ductility (ability to be drawn into wires). Metals typically have a crystalline structure and are found naturally in solid form (with the exception of mercury, which is a liquid at room temperature).

Metals make up a large portion of the periodic table of elements, with examples including iron, copper, gold, silver, aluminum, and titanium, among many others. Metals are essential in various industries such as construction, manufacturing, electronics, transportation, and energy production due to their unique properties and versatility.

Metals are generally dense materials. Density is a measure of how much mass is contained in a given volume. Metals tend to have high densities because their atoms are closely packed together in a crystalline structure. This close packing of atoms contributes to their characteristic properties such as strength, malleability, and conductivity.

However, it's important to note that the density of metals can vary widely depending on factors such as their elemental composition, crystal structure, and any impurities present. For example, some metals like lead and platinum are denser than others like aluminum or magnesium.