DEVELOPMENT OF ATOMIC MODEL

1. JOHN DALTON

• Elements are made up of small particles called ATOMS
• Atom is spherical
• Can't be created, destroyed or divided
• Atoms of the same element are identical

2. J. J THOMSON

• Discovered that electrons are negatively charged.
• Atom has positive charge
• Atom has electrons scattered inside it
• "Plum Pudding" model

3. ERNEST RUTHERFORD

• Nucleus has positive charge particles, proton
• Electrons always orbit the nucleus
• no. of proton = no. of electrons
• mass of atom centres at nucleus

4. NEILS BOHR

• Electron rounds the nucleus in the shell (circular shape)
• Each shell has fixed distance from nucleus

5. JAMES CHADWICK

• All nuclei consists of neutron & proton
• Electron rounds the nucleus in shell
• Mass of neutron equal to mass of proton

ACROSTIC

Daddy                    --->           Dalton

Takes                     --->           Thomson

Racket                   --->            Rutherford

Back                      --->             Bohr

Chicago                  --->            Chadwick