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Q & A: Active Metals

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Most recent answer: 10/22/2007
Q:
What are Active metals
- Maria (age 12)
Lahore Pakistan
A:
Active Metals is a collective name for metals that react strongly or quickly with other substances. The metals in the first column of the periodic table are very reactive with other substances because they have a single electron in their outermost shell, just waiting to be stripped off to form a complete shell in some other atom, like oxygen or fluorine or chlorine, to form oxides, fluorides or chlorides. Examples of active metals are Lithium, Sodium, Potassium, Rubidium, and Cesium, which are also known as the "Alkali" metals. Sodium and Cesium I have seen first-hand create explosive reactions with water -- they want to react so much with water molecules they will displace one of the hydrogens in the H2O molecule to make NaOH, for example, and emit hydrogen gas, which then burns (or explodes). Metals and other elements are characterized in their reactivity by their "electron affinity" or "electronegativity".

Pure calcium is also very reactive, as are other metals in its column. Some metals are not very reactive at all. Gold hardly tarnishes or reacts with much of anything, and platinum is even more impervious to chemical attack (although it can catalyze some reactions). Copper and Zinc are reactive enough in an acid environment to make a battery (see our answers on lemon batteries elsewhere on the site). It is a mistake to join a copper pipe to a zinc one in household plumbing -- the joint will conduct electricity and speed the corrosion of the pipes.

Tom

(published on 10/22/2007)

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