Sub-Atomic Particles

In 1808, according to John Dalton, matter was made up of extremely small, indivisible particles called ‘atoms’. The word ‘atom’ has been derived from the Greek work ‘a-tomio’ which means ‘uncut-able’ or ‘non-divisible’.

But according to Bohr, J. J. Thomson, Rutherford, Chadwick and other scientists prove that atom was not the smallest indivisible particle but had a complex made up of electrons, proton, neutrons etc. At present, about 35 different subatomic particles are known but the three particles namely electron, proton and neutron are regarded as the fundamental particles.

Atom consists of sub-atomic particles such as electrons, protons and neutrons. The electrons are negatively charged particles and are present in the. The protons are positively charged particles and are present in the nucleus of the atom. The neutrons are neutral particles and are present in the nucleus along with the protons.