One of the earliest known and most useful families of chemical elements were the metals. They are easy to distinguish from nonmetals.
Most metals are good conductors of heat and electricity.
Most can be drawn smoothly into wire and they can be hammered into sheets. Because of their strength, conductivity, and their ability to be reworked into different forms, metals are indispensable to modern technology. About three quarters of all the known chemical elements are metals. There is such a variety that not all metals can be described by a single definition. Sodium and potassium, for example, are soft enough to be cut with a knife.