Question

Why are metals at the bottom of reactivity series found in Earth's crust in Free State?​

Answer 1

Answer:

Source of metal: Metals occur in earth's crust and in sea water; in the form of ores. ... Metals found at the bottom of reactivity series are least reactive and they are often found in nature in free-state; such as gold, silver, copper, etc. Copper and silver are also found in the form of sulphide and oxide ores

Answer 2

Answer:

Metal extraction and the reactivity series

Metals are extracted from ores, which are minerals found in the Earth’s crust that contain metal compounds. Examples of ores include:

haematite (Fe2O3)

bauxite (Al2O3)

galena (PbS)

The method used to extract a metal from its ore depends upon the stability of its compound in the ore, which in turn depends upon the reactivity of the metal.

Very reactive metals, such as aluminium, form stable oxides and other compounds. Electrolysis is commonly used to extract these metals and requires a lot of electric current (energy) to reduce them to extract the metal.

Less reactive metals, such as iron, form less stable oxides and other compounds. Reduction with carbon is often used to extract these metals and requires less energy to reduce them to extract the metal.

Therefore, the method of extraction of a metal from its ore depends on the metal’s position in the reactivity series.

Metals more reactive than carbon, such as aluminium, are extracted by electrolysis, while metals less reactive than carbon, such as iron, may be extracted by reduction with carbon.

As gold is so unreactive, it is found as the native metal and not as a compound. It does not need to be chemically separated. However, chemical reactions may be needed to remove other elements that might contaminate the metal

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