Changing Models of the Atom

What is the charge of an alpha particle?

• +2

• -2

• 0

• +1

Which ideas came from the plum pudding model?

• The atom cannot be broken down.

• The atom contains electrons that orbit a positive nucleus.

• The atom is made of electrons contained in a 'soup' of positive charge.

• Electrons must be part of the atom since solids rub together to produce static electricity.

Why were alpha particles used in the Rutherford scattering experiment?

• They had a small mass

• They have a neutral charge

• They are about the same size as atoms

• They are easy to fire at a target

A vacuum was used in the experiment so that alpha particles would not ____________ the air molecules.

Name two parts of apparatus involved in the experiment

• Thin copper foil

• Fluorescent screen

• A bulb

• Thin gold foil

What happens to the alpha particles in the Rutherford scattering experiment?

• They all go straight through the gold foil

• A small number are deflected at large angles

• Most go through the gold foil

• Nearly all of them deflect backwards from the gold foil

Since there was a very small number deflected backwards, this was evidence that the atom contained a ____________.

How does the Bohr model describe the different coloured flames of burning chemicals?

• Electrons are in specific energy levels

• Protons and neutrons are in a nucleus

• Electrons orbit a nucleus

• Electrons are in a 'soup' of positive charge

State two differences between the Bohr model and the plum pudding model

What were the conclusions from the Rutherford scattering experiment?