Very Short Question and Answers - Occurrence of Metals

A mineral is a naturally occurring substance containing metals or their compounds along with impurities like soil and sand.

An ore is a mineral from which a metal can be extracted profitably and easily.

Gangue is the unwanted or earthy impurities present in the ore.

All ores are minerals, but all minerals are not ores. Ores contain enough metal to allow profitable extraction, while minerals may not.

The native state refers to metals found in their pure, uncombined metallic form in nature due to low reactivity.

Gold (Au) and Platinum (Pt) are commonly found in the native state.

Copper (Cu) can be found both in its native state and in combined forms.

Gold and platinum are least reactive, so they do not combine easily with other elements and thus are found uncombined in nature.

Mercury is mostly found as its sulphide ore called cinnabar (HgS).

Metals commonly occur as oxides, sulphides, and carbonates.

Common iron ores are Hematite (Fe₂O₃), Magnetite (Fe₃O₄), Limonite (Fe₂O₃·nH₂O), Siderite (FeCO₃), and Iron pyrites (FeS₂).

Bauxite (Al₂O₃·2H₂O) is the chief source of aluminium.

The main ore of lead is Galena (PbS).

Sodium is obtained from Rock salt, whose formula is NaCl.

Mining is the process of extracting ore from the earth.

It is the process of removing gangue from the ore to enrich its metal content.

Roasting involves heating sulphide ores strongly in the presence of air to convert them to oxides.

Calcination is heating carbonate or hydrated ores in limited air to convert them into oxides.

Most metals are reactive and combine with other elements like oxygen or sulphur, so they are found as compounds in ores.

A metal’s position in the reactivity (activity) series determines if it is found in native or combined state; less reactive metals occur native, while more reactive ones occur combined.