Alpha Scattering and Nuclear Model:

Question 1

What is the plum pudding model?

Answer 1

• Atom is a ball of positive charge.
• ## Negative electrons embedded into it.

Question 2

What is the alpha scattering experiment?

Answer 2

• Gold is hammered to one atom thick.
• Alpha Particles (positive charge) are fired at the golden foil.

1) most alpha particles pass straight through the golden foil without changing direction.
2) some alpha particles are deflected so changed direction as it passes through the golden foil.
3) some alpha particles bounced back.

Question 3

What did these results show?

Answer 3

• some alpha particles went through the gold foil without changing direction:
• ATOMS ARE MOSTLY EMPTY SPACE.
• some alpha particles were deflected (changed direction).
• Centre of atom must have positive charge that when particles went close got repelled.
• some alpha particles were bounced back:
• Mass of the atom is concentrated at the centre. Nuclues.
• Around the edge is negative electrons.

Question 4

What did Neils Bohr suggest?

Answer 4

• Electrons orbit the nucleus at specific distances

- Orbits are called energy shells.

Question 5

What did James Chadwick find?

Answer 5

• Nuclues contains nuetrons.
• ## Have no charge, nuetral.