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== Metals in chemistry ==
In [[chemistry]], metal is a word for a group of chemical [[chemical element|elements]] that have certain [[properties]]. It is easy for the [[atom]]s of a metal to lose an [[electron]] and become positive [[ion]]s, or [[cation]]s. In this way, metals are not like the other two kinds of elements - the [[nonmetal]]s and the [[metalloid]]s. Most [[chemical element|elements]] on the [[periodic table]] are metals.

On the [[periodic table]], we can draw a zigzag line from the [[chemical element|element]] [[boron]] (symbol B) to the [[chemical element|element]] [[polonium]] (symbol Po). The elements that this line passes through are the [[metalloid]]s. The elements that are above and to the right of this line are the [[nonmetal]]s. The rest of the elements are the metals.

Most of the properties of metals are due to the fact that the [[atom]]s in the metal do not hold onto their [[electron]]s very tightly. Each atom is separated from the others by a thin [[layer]] of [[valence]] [[electron]]s.

However, some metals are different. An example is the metal [[sodium]]. It is [[wikt:soft|soft]], melts at a low [[temperature]], and is so [[density|light]], it [[wikt:float|float]]s on [[water]]. People should not try this though, because another property of [[sodium]] is that it [[Explosion|explodes]] when it touches [[water]].

Most metals are [[chemical]]ly [[stable]], and do not [[Chemical reaction|react]] easily, but some do. The reactive ones are the [[alkali]] metals like [[sodium]] (symbol Na) and the [[Alkaline earth metal|alkaline earth metals]] like [[calcium]] (symbol Ca). When metals do react, they often react with [[oxygen]]. The [[oxide]]s of metals are [[Base (chemistry)|basic]]. The [[oxide]]s of [[nonmetal]]s are [[acid]]ic.

[[Chemical compound|Compounds]], which have metal [[atom]]s combined with other [[atom]]s to make [[molecules]], are probably the most common substances on Earth. For example, common [[salt]] is a [[chemical compound|compound]] of [[sodium]].