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| | Metal - Wikipedia, the free encyclopedia |
 | | The metals are one of the three groups of elements as distinguished by their ionisation and bonding properties, along with the metalloids and nonmetals. |
 | | Some metals form a barrier layer of oxide on their surface which cannot be penetrated by further oxygen molecules and thus retain their shiny appearance and good conductivity for many decades (like aluminium, some steels, and titanium). |
 | | Traditionally, metals have certain characteristic physical properties: they are usually shiny (they have "luster"), have a high density, are ductile and malleable, usually have a high melting point, are usually hard, and conduct electricity and heat well. |
| en.wikipedia.org /wiki/Metal (662 words) |
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