Metalchemistry, a metal is a word for a group of elements that have certain properties. It is easy for the atoms of a metal to lose an electron and become positive ions, or cations. Atoms of a metal usually form ionic bonds with other atoms. In this way, metals are not like the other two kinds of elements - the nonmetals and the metalloids.
On the periodic table, we can draw a straight line from the element boron (symbol B) to the element polonium (symbol Po). The elements that this line passes through are the metalloids. The elements that are above and to the right of this line are the nonmetals. The rest of the elements are the metals.
Lumps of metals behave in similar ways. Most metals melt at a high temperature. They are usually hard, and they have a high density. Heat and electricity move through metals easily. Metals are often shiny. Lumps of metal can be hammered into thin sheets - we say that they are malleable. They can be pulled into thin wires - we say that they are ductile. Most of these facts are because the atoms in the metal do not hold onto their electrons very tightly. Each atom is separated from the others by a thin layer of valence electrons.
Most metals are chemically stable, and do not react easily. (Some of the metals do react. These metals are the alkali metals like sodium (symbol (Na) and the alkaline earth metals like calcium (symbol Ca).)
Most of the world is made of nonmetals. However, most of the elements on the periodic table are metals.
Not all metals are elements. Most of the metals we use are mixtures, called alloys. An alloy is any mixture that acts like a metal and has at least one metallic element in it. Some common alloys are
- steel (iron and carbon)
- brass (copper and zinc)
- bronze (copper and tin)
- duralumin (aluminium and copper)
In astronomy, a metal is any element other than hydrogen or helium. This is because these two elements (and sometimes lithium) are the only ones that form outside stars. Signs of metallic elements in a nebula or some other place in the sky mean that stars were there.