ABSTRACT
We have already heard about atoms. Continuing along the
line of ancient Greek scientists and considering the wealth
of experimental results obtained in the post-Renaissance
phase, Dalton said that everything must be composed of
atoms. An element consists only of one kind of atoms.
For example, take iron. All iron atoms are exactly alike.
Similarly, metals like aluminium, copper, gold, silver, zinc
or gases like hydrogen, nitrogen, oxygen or materials like
diamond, mercury, sulphur — all of these are elements.
Ninety-two such elements have been found in nature.
