1. 08/11/2013 What level will you reach?... To get a grade D: you will label the sub- atomic particles in an atom and state the charge of the sub-atomic particles in an atom To get a grade C: you should define atomic (proton) number To get a grade B: you should describe how the elements are ordered in the periodic table To get a grade A/A*: you should explain why atoms are electrically neutral

2. 08/11/2013 Structure of the atom A hundred years ago people thought that the atom looked like a plum pudding – a sphere of positive charge with negatively charged electrons spread through it… I did an experiment that proved this idea was wrong. I called it the Rutherford Scattering Experiment Ernest Rutherford, British scientist:

3. 08/11/2013 The Rutherford Scattering Experiment Alpha particles (positive charge) Thin gold foil Some particles passed through, some were deflected backwards Conclusion – atom is made up of a small central nucleus surrounded by electrons orbiting in shells

4. 08/11/2013 The structure of the atom ELECTRON – negative, mass nearly nothing PROTON – positive, same mass as neutron (1) NEUTRON – neutral, same mass as proton (1)

5. 08/11/2013 The structure of the atom ParticleRelative MassRelative Charge Proton11 Neutron10 Electron0 MASS NUMBER = number of protons + number of neutrons SYMBOL PROTON NUMBER = number of protons (obviously)

6. 08/11/2013 Group 7

7. 08/11/2013Neon

8. Quick quiz…what have you learnt? 1.What is the atomic number of helium? 2.How many protons does an atom of lithium have? 3.What is the mass number of lithium? 4.How many protons does an atom of fluorine have? 5.How many neutrons does an atom of beryllium have? 6.What is the atomic number of oxygen? 7.How many protons does an atom of oxygen have? 8.How many electrons does an atom of oxygen have? 9.What is the mass number of aluminium? 10.How many protons, neutrons and electrons does an atom of aluminium have?

9. 08/11/2013 What level did you reach?... To get a grade D: you will label the sub- atomic particles in an atom and state the charge of the sub-atomic particles in an atom To get a grade C: you should define atomic (proton) number To get a grade B: you should describe how the elements are ordered in the periodic table To get a grade A/A*: you should explain why atoms are electrically neutral