↪ About seventy five percent of the elements of the periodic table are metals.

↪ Elements of the periodic table are not classified on the basis of metals, metalloids and nonmetals.
↪ But division of elements of the periodic table into s, p, d and f blocks, the most electropositive metals are found to be grouped in s block (except H, a nonmetal), highly tensile and hard metals in d and I blocks, some poor metal, a few semi metals (metalloids) and rest of the elements as non metals in p block.

⁕ Metals

↪ They are solids (except Hg), lustrous, malleable, ductile and good conductor of electricity having atomic electrical conductivity greater than 10^-3scm^-4mol^-1 which decreases with the increase of temperature.
↪ Metal oxides possessing their group oxidation number are basic in general.

⁕ Metalloids 

↪ They are dull solids, not malleable and ductile e.g., B, Si, Ge, As, etc.
↪ They are poor electrical conductor and have atomic electrical conductivity less than 10^-3s cm^-4mol^-1 and greater than 10-5 scm^-4mol^-1 approximately.
↪ They increase conductivity with the rise of temperature and presence of impurities. They possess properties partly of metals and partly of non metals and so they are called semi metals.
↪ They form amphoteric oxides.

⁕ Non metals 

↪ They are gases, solids and bromine is the only liquid non metal.
↪ They are not malleable and ductile and bad conductor of electricity and have atomic electrical conductivity less than 10^-10s cm^-4mol^-1.
↪ They form mostly acidic oxides and a few NO, CO, H₂O are neutral.

Differences between Metals, Metalloids and Non Metals