_______________ is the positively charged particles in an atom.

________________ is the electrons in its valence shell forming an anion.

_______________ discovered that cathode rays have kinetic energy and raise the temperature of a metallic object on which they fall.

______________ was an ancient greeck philosopher studied the nature of the matter and the basic constituents of all substance.

_____________ gains two electrons in its valence shell forming an anion.

_____________ gains three electron in its valence shell forming an anion with three negative charge.

Oxygen has_________ isotopes.

Uranium has ________________ isotopes.

________________ proposed a theory of atom known as the atomic theory.

According to _______________ atomic theory atoms consisting of subatomic particles like electrons ,protons and neutrons.