Page 137 - Science Class 6 Times Publication

Metalloids

The elements which show the properties common to both metals and
non-metals are called metalloids. The metalloids resemble metals
in some of their properties while they resemble non-metals in other
properties. Silicon, arsenic, germanium, etc are some metalloids.
Some of the common properties of metalloids are as follows:

a. Metalloids are either solid or liquid at ordinary temperature.
b. They are poor conductors of heat and electricity.

c. They are found in powder form.
d. They have metallic lustre.

e. They are not malleable and ductile.

Alloys

When metals are heated strongly, they melt to turn into liquid state.
The liquid states of metals can be mixed with each other to form a
homogeneous mixture. The mixture then becomes
solid on cooling. The homogeneous mixture of two or
more metals or metals and non-metals is known as
alloy. Steel, brass, bronze, etc are some examples of
alloys.

Steel is an alloy of iron and carbon. It is used for numerous purposes.
It is used for making knives, swords, tools, machines, household
appliances, etc. Similarly, brass is an alloy of copper and zinc. Bronze
is an alloy of copper and tin.

Some important metals

Iron

Iron is one of the oldest known and the most essential metals. It is
the second most abundant metal found in the earth’s crust. About
6.2% of the earth’s crust is made up of iron. But iron is not found
in free (pure) state. It is found in the form of compounds such as
haematite, magnetite, iron pyrite, etc. These compounds are called
ores of iron. The pure form of iron is obtained from the ores using
several processes.

Times' Crucial Science and Environment 133 Book 6