Structure of Atom Class-11th

In this unit we start with the experimental
observations made by scientists towards the end of
nineteenth and beginning of twentieth century. These
established that atoms can be further divided into subatomic particles, i.e., electrons, protons and neutrons—
a concept very different from that of Dalton. The major
problems before the scientists at that time were:
• to account for the stability of atom after the discovery
of sub-atomic particles,
• to compare the behaviour of one element from other
in terms of both physical and chemical properties,