What is the importance of the chapter Atoms? Why do we study the chapter Atoms? How many marks are carried by the chapter Atoms in class 12 board examinations? What is the Rutherford Nuclear Model of Atom? Explain Bohr’s model of Atom? Where is the mass of an atom located? What is the change of Nucleus? How stable is Nucleus
The entire positive charge and most of the mass of the atom is concentrated in the small volume called nucleus. The negative change of the electron is equal to the positive change if the nucleus. So the whole atom is neutral. The electrons are revolving around the nucleus in different orbits and necessary centripetal force is provided by the electrostatic force between electron and nucleus. Electrons can revolve only in those orbits where the angular momentum is integral multiple of h/2pie. While revolving in orbits electrons do not radiate energy. When energy is supplied to the atom it jumps from lower level orbit to higher level orbit and later returns to any lower energy orbit. During this time it radiates energy in the form of electromagnetic waves.