![]() These are extracted by melting the oxide at a very high temperature and running an electric current through the molten stuff. It took much longer to figure out how to extract the more reactive elements like magnesium, aluminum and lithium. Of course, as we found out in the previous topic, once they realised that if they melting and mixed them a stronger metal alloy was formed, which lead to the Bronze Age. One can imagine the prehistoric men surrounding a camp fire with rocks and noticing the formation of copper, and perhaps the other metals. A common form of reducing metals is called 'smelting' and can be done for copper, tin, silver, zinc, iron and lead and involves reacting the compound with carbon (soot). The process of extracting the metal from a metal compound is called 'reduction'. The earliest metals that were discovered were the less reactive ones, which must have been discovered by accident. The rest are found in the Earth's crust as mineral compounds in the rocks. Only the non-reactive metals such as gold and platinum are found in their elemental form. The test for hydrogen is the famous 'squeaky pop' test!Īnother valuable insight given by the reactivity series is how metals are made in the first place. Hydrogen is highly flammable, so can be ignited by the heat of the reaction. Obviously reacting lithium et al with even a dilute acid would be insanely dangerous - SO WE DON'T DO IT! Recall from the previous topic the patterns/rules for making salts. Dilute acids more so.Īn example would be dropping magnesium into sulphuric acid: These salts are usually soluble, so give a clear solution. The reaction is similar as hydrogen is released, but a salt is produced instead. So, if we want to get some more exciting chemistry to be able to determine which metals are more reactive than the others, we need to use acid rather than water. Heating the water up will speed up the reaction a bit - see animation below. You saw that when I left a clean strip of magnesium in a beaker of water for a weekend it turned black, but only at the surface. Most react in a very slow and boring manner - taking days if not weeks to corrode. You have seen that some metals react in a big way when they meet water. The hydrogen from the water is released, and if heated enough by the reaction can explode! Lithium is famous now as it is the metal that is found in laptop and phone batteries. They react violently with water to produce a hydroxide, which is alkaline. By far the most reactive metals are the so-called ALKALI METALS. It is ridiculously difficult to isolate the pure metal from its tightly bound oxides. This is why the highly reactive metals lithium, sodium and potassium are SO expensive. The more REACTIVE a metal is, the faster it reacts with oxygen and the harder it will be to separate it from the oxygen again. It can be removed by polishing (abrading it) or dropping it in an acid (cola!). The gradual deterioration of a copper coin is the formation of a layer of tarnish. ![]() Some oxides are called tarnish, copper is an example of this. The precious metals are very unreactive and can be found in perfect condition, even after hundreds of years. For example: iron reacts with oxygen to produce iron oxide (usually called rust). Almost every metal reacts with oxygen to create a surface layer of oxide.
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