Page 39 - Science Class 08

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Metals and Non–Metals

• Metals • Extrac on
• Physical Proper es of Metals • Chemical Proper es of Metals
• Uses of Metals • Corrosion • Prevailing Corrosion

Metals are opaque, lustrous elements that are terms, a mineral has four basic features.
good conductors of heat and electricity. Most These four basic features are:

metals are malleable and duc le and are, in
v It occurs in nature and cannot be made
general, denser than the other elemental
ar ficially.
substances.
v It is formed from substances that were
Metals are one of the four classes of minerals—
never alive.
metals, metalloids, non-metals and gems.
v Wherever it may occur, it has the same
Minerals are called so because most of them are
chemical make-up.
mined from under the ground. But in scien fic
v Its atoms are arranged in regular pa erns
so as to form crystals.

Till recently, fossil fuels, petroleum, coal and natural gas were also considered to be minerals
because they are obtained from under the earth. But, in fact, fuels are totally different from
minerals as they are formed from organic (living) materials buried under the ground. As for
minerals, they are formed from substances that were never alive.

Ninety two (92) elements occur in nature and most of them are metals. Only about 20 of them
are non-metals. These two groups of elements have opposite proper es. Let us read about
these two classes of minerals in detail.

METALS mixed with other minerals. Very few metals

Most metals occur in ores which are called occur in free state. They include gold, silver,
metallic minerals also. But these minerals are pla num, copper and mercury. Their ores do

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