What are metals, non-metals and metalloids?

Metals: Metals are generally solids at room temperature (mercury is an exception), lustrous, malleable, ductile, high melting and boiling points and good conductors of heat and electricity. Metals comprise more than 75% of all known elements and appear on the left side of the perodic table. For example iron, copper, aluminium, lead etc. The elements become more metallic as we go down a group.
Non-metals: Non-metals are usually solids or gases at room temperature, non-lustrous, low melting and boiling points and poor conductors of heat and electricity. They are located at the top right hand side of the periodic table. For example oxygen, hydrogen, carbon, sulphur, etc.

The non-metallic character increases as we go from left to right across the periodic table.

Metalloids or semimetals: These are the elements which show common characteristic of metals and non-metals. For example, germanium, silicon, arsenic, antimony and tellurium.