P7 Radioactivity

Question 1

Models of the atom in order

Answer 1

• Solid Sphere model -> John Dalton
• Plum Pudding model -> J.J. Thomson
• Nuclear model -> Ernest Rutherford
• Bohr model -> Niels Bohr

Question 2

Plum Pudding model

Answer 2

• Sphere of positive charge with negatively charged electrons spread through it
• The discovery of electrons led to this model

Question 3

Rutherford’s gold foil experiment

Answer 3

• Firing alpha particles at a gold foil
• Expecting all the particles to go through -> lots of empty space in the atom
• Some particles were reflected and a few were deflected -> small positively charged ball at the centre