Metals are those elements which possess the following properties-
1) They are generally solid at room temperature .
Exception – mercury is liquid metal.
2) They possess high density .
Exception – Alkaline earth metals have low density .
3) They are good conductor of heat and electricity.
4) They are malleable and ductile.
5) They possess generally high melting and boiling points.
6) They form basic oxides.
Ex. Na2O, CaO
7) They form non-volatile hydrides with hydrogen.
8) They are monoatomic in nature.
9) They are lustrous in nature.
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1) They are brittle in nature.
2) Six of the nonmetals like carbon , boron , phosphorous , sulphur, selenium and iodine are solid.Bromine is the only liquid nonmetal at room temperature.Other nonmetals are gases like oxygen, nitrogen, fluorine , chlorine, hydrogen, helium, argon , neon, krypton, xenon, radon .
3) They are non-lustrous.
Exception – Iodine
4) Their oxides are acidic or neutral.
Ex. CO2, SO2
5) They form volatile hydrides.
6) They have low melting and boiling points.
Exception – Diamond
7) They are non – conductor of heat.
Exception – Graphite
Metalloids or Semimetal-
Elements which have some properties of both metals and nonmetals are called metalloids.
Ex. silicon , germanium , arsenic, antimony and tellurium.
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