Sun April 20, 2014 By: Janvi Jhanga

what is the difference between atom and molecules ,

and in element and substance ....

Expert Reply
Mon April 21, 2014



Atom is a smallest particle of an element.

Molecule is a group of two or more atoms combined together.

Atom consists of nucleus (containing protons and neutrons) and electrons.

Molecule consists of combination of two or more same or different atoms chemically bound together. e.g. H2, HCl, NaCl etc.

Atom can neither be seen through naked eye nor through magnifying microscope.

Molecule is not visible to naked eye, while can be seen through highly magnifying microscope.

Atom cannot be further divided.

Molecule can further be divided to give individual atoms.

Atoms may or may not have independent existence.

Molecules are capable of having independent existence.

For example, atom of oxygen (O) has no independent existence while its molecule exists as O2 in nature.

Atom has nuclear bond or attraction within it i.e. it involves electrostatic attraction between the positive nucleus and electrons.

Molecule has chemical attraction or bonding between the atoms i.e. it involves single, double or triple bonds between the atoms.

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