1. The atom

2. Atoms Atoms are the thought of as the smallest part of an element They are formed from three different sub- atomic particles These are call protons, neutrons and electrons

3. The sub-atomic particles ParticleChargeMass Proton Electron Neutron Complete the following table +1 0 1 1 1 / 1850

4. The Atom This is the nucleus It contains all the protons and neutrons This is one electron Electrons are always present in shells

5. C 6 12 Atomic Number All elements on the periodic table are shown like this This is the elements symbol This is carbon This is the elements atomic number

6. What does the atomic number tell us? The atomic number tells us how many protons an element’s atom has. This is the same as the number of electrons So carbon has 6 electrons Sodium’s atomic number is 11. So it has 11 electrons Oxygen has an atomic number of 8. how many electrons does it have? How many electrons does chlorine have Which has more electrons bromine or calcium?

7. Electron Shells The first electron shell can have up to two electrons The second electron shell can have up to eight electrons The third electron shell can have up to eight electrons

8. Carbon’s Electron Shells Carbon has 6 electrons Two electrons can go in the first shell There are four electrons left These can go into the 2 nd shell The electron configuration is written as 2. 4

9. The outer shell The number of electrons in the outer shell of an atom is the same as the group of the atom For example, carbon has four electrons in its outer shell and it is in group four

10. Question Time 23 Na 11 56 Fe 26 119 Sn 50 19 F 9 27 Al 13 11 26 50 9 13 How many protons do the following elements contain?

11. Question Time

12. Make your own atom