Question

Make a project report on different models suggested by different scientist regarding the structure of an atom.

Answer 1

J.J Thomson model of atom- Thomson purposed a model of atom in 1904 . An atom is a sphere of positive electricity in which no. of electrons are embedded to nutralize the positive charge. This may be compared with watermelon in which seeds are embedded. This model of atom is called Thomson model of atom.
Rutherford's Model of atom- Discovery of nucleus through scattering experiment . Rutherford's perform a experiment in which he bombarded a thin layer of heavy metal(gold) with a beam of fast moving alpha particles which has charged as helium ions . These alpha particles are obtained from radium placed in the cavity of block of lead and made into a fine beam with a slit. Rutherford's observed the scattering of alpha Ray's after hitting the foil placed in a circular zinc sulphide screen around the metal foil.
Bohr's model of atom- He purposed that an atom consists of small heavy positively charged nucleus in the center and the electrons revolve around it. In a atom the orbit in which electrons revolve around are the discrete orbit having fixed energy and radius. These orbits are called energy levels or shells. These shells are named as K,L,M,N or numbered as 1,2,3,4... If energy of the orbit is fixed they are called stationary states . As long as electron is revolving in a particular orbit, it can neither lose Nor gain energy. This the atom is stable and does not collapse . This state with lowest energy is called ground state of atom. The energy is lost or gain by a electron when it jump from one orbit to another. The energy is gain or absorb when it jump from inner shell to outer shell. The energy is emitted or loose when it jump back to it's inner shell or energy level.

Hope u understand this concept of atom .