Atoms - Atoms & Molecules : Notes, Class 9 Science PDF Download

Atoms and Molecules

Atoms:

 On the basis of Dalton’s Atomic  On the basis of Dalton’s Atomic Theory atom can be defined as the smallest particles of matter are called atoms.

Other characteristics of atoms:

• Atom is the smallest particle of matter.

• AAll elements are made of tiny particles called atom.

• Atoms are very small in size and cannot be seen through naked eyes.

• Atom does not exist in free-state in nature. But atom takes part in a chemical reaction.

• The properties of a matter depend upon the characteristics of atoms.

• Atoms are the building block of an element similar to a brick which combine together to make a building.

• The size of atoms is indicated by its radius.

• In ancient time atoms was considered indivisible.

Symbols of Atoms of Elements

For convenience elements are represented by unique symbols. For example: Hydrogen is represented by ‘H’. Oxygen is represented ‘O’. Nitrogen is represented by ‘N’. Iron is represented by ‘Fe’. ments are represented by unique symbols. For example: Hydrogen is represented by ‘H’. Oxygen is represented ‘O’. Nitrogen is represented by ‘N’. Iron is represented by ‘Fe’.

His worked proved as boon to science. For his marvelous work Berzilius, together with John Dalton, Antoine Lavoisier, and Robert Boyle is considered as the Father of Modern Chemistry.

Symbol of many elements are taken from their English name, while symbol of many elements are taken from their Greek or Latin names.

Symbol of some element which are derived from their Latin name

Several elements are named after the place where they discovered, such as ‘Copper’ which was taken from Cyprus. Some elements are named after their colour, such as ‘Gold’ which means yellow.