Prior to thomson's discovery, the atom was thought to be indivisible. explain the significance of thomson's concept of the electron.

His "plum pudding" model (1904) suggested: the electrons are embedded in the positive charge.  

Tomson concluded that atoms are divisible and that the corpuscles are their building blocks (atoms are made up of smaller particles).

J. J. Thomson discovered the electron in 1897.  

With this model, he abandoned his earlier hypothesis (the atom was composed of immaterial vortices).

electrode materials and found that the properties of the cathode ray remained constant no matter what cathode material he used.

J.J. Thomson placed two oppositely charged electric plates around the cathode ray. He did experiments using different metals as electrode materials and found that the properties of the cathode ray remained constant no matter what cathode material he used.