Chemistry unit 1.3 The development of the model of the atom

Question 1

What can new experimental evidence lead to?

Answer 1

A scientific model being changed or replaced.

Question 2

What was the idea before the discovery of the electron?

Answer 2

Atoms were thought to be tiny spheres that cannot be divided.

Question 3

Order of history of the atom

Answer 3

• John Dalton, atoms are tiny spheres and cant be divided.

-JJ Thompson, found electrons and ‘plum pudding model’ found, ball of positive charge with electrons embedded in.

-Ernest Rutheford, alpha particle scattering experiment, mass of atom was concentrated at centre (nucleus) and nucleus was charged. (nuclear model)

-niels bohr
electrons orbit nucleus at specific distances.

-ernest rutherford( protons) positive charge of any nucleus subdivided into smaller particles, each particle having the same amount of positiv charge

-james chadwick
(neutrons)