Y9 Chemistry Xtra

Question 2

1st Atom Model

Answer 2

The SPHERICAL MODEL

JOHN DALTON

1803

Atoms are tiny particles that can’t be broken down

Atoms of the same element are identical to each other

During chemical reactions, atoms re-arrange to make different substances

Question 3

2nd Atom Model

Answer 3

The PLUM PUDDING MODEL

J J THOMPSON

1897

Atoms are spheres of positive charge

Electrons are embedded inside, making it naturally charged

Question 4

3rd Atom Model

Answer 4

The PLANETARY MODEL

ERNEST RUTHERFORD

1904

Thought atom had central positive nucleus

Thought atom is mostly empty space

Said nucleus is surrounded by negative electrons

Question 5

4th Atom Model

Answer 5

The GOLD FOIL EXPERIMENT

GEIGER and MARSDEN

1909

Tested Plum Pudding Model

Aimed positively-charged particles at thin gold foil

Some passed through as expected, some changed direction

Thought electrons were deflected by central nucleus

Question 6

5th Atom Model

Answer 6

The ORBITAL MODEL

NEILS BOHR

1913