History Of The Atom

Question 1

John Dalton - Billiard Ball model

Answer 1

Matter is composed of tiny invisible particles - atoms
Chemical reactions consist of rearranging atoms in simple whole ratios

Question 2

Joseph Thomson - Plum Pudding

Answer 2

Atoms consist of sphere - uniform positive charge embedded with negativity charged particles

Question 3

Ernest Rutherford - Nuclear model

Answer 3

Small positively charged nucleus - most of mass of atom
No. of protons = no. of electrons
Large volume around nucleus - electrons move

Question 4

Niels Bohr - Planetary model

Answer 4

Electrons move in fixed orbits. Electrons can jump orbits (shells)
When electrons fall back to original orbit - energy is loss as radiation

Question 5

James Chadwick

Answer 5

Nucleus contains neutrons - electrically neutral particles with a mass similar to that of a proton