Models of atoms

John Dalton : 

John Dalton POSTULATES of Dalton’s Atomic Theory All matter consists of tiny particles called atoms. Atoms are indestructible and unchangeable. Elements are characterized by the mass of their atoms. The atoms of one particular element are all identical in mass and other properties. When elements react, their atoms combine in simple, whole-number ratios to form compounds.

Plum Pudding Model : 

Plum Pudding Model - J J Thompson

Slide 3: 

Expected Result α-Ray Scattering Gold Foil Experiment

Rutherford’s Model : 

Rutherford’s Model

Rutherford’s Nuclear Model Of an Atom : 

Rutherford’s Nuclear Model Of an Atom POSTULATES: Most of the space in an atom is empty. Each atom has a small dense positively charged nucleus in the centre. The nucleus consists of positively charged protons. Negatively charged Electrons revolve around the nucleus. The number of electrons is equal to the number of protons to make the atom neutral.

Bohr’s Model : 

Bohr’s Model Shells K L M N

Bohr’s Planetary Model : 

Bohr’s Planetary Model POSTULATES: Atoms consist of a central nucleus made up of protons and neutrons. Electrons revolve around the nucleus in fixed orbits called shells. The shells are numbered K,L,M,N…(1,2,3,4…) from inside out. Further the shell from the nucleus-more is its energy. Electrons neither gain nor loose energy as long as they stay within the shell. Electrons gain or loose energy as they go from one shell to another.