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Electrons Electrons Electrons

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Presentation on theme: "Electrons Electrons Electrons"— Presentation transcript:

1 Electrons Electrons Electrons

2 Electron Configuration… Just a bunch of circles….? Not quite!

3 Electron Arrangement The electrons that surround the nucleus of an atom are arranged in shells . Each shell has a maximum number of electrons that can exist in that shell.

4 Up to 2 electrons can exist in the first shell
Up to 8 electrons can exist in the second and third shell Up to 18 electrons can exist in the fourth and fifth shell 8 2 8

5 Basic Atom Electron Nucleus Shell or Orbit

6 Beryllium Atom Electrons Protons Neutrons

7 Boron Atom Electrons Protons Neutrons

8 Carbon Atom Electrons Protons Neutrons

9 Nitrogen Atom Electrons Protons Neutrons

10 Oxygen Atom Electrons Protons Neutrons

11 Fluorine Atom Electrons Protons Neutrons

12 Neon Atom Electrons Protons Neutrons

13 Sodium Atom Electrons Protons Neutrons

14 Drawing electron dot diagrams
We can draw diagrams to show the arrangement of the electrons in each element. This is called an electron dot diagram Note the example below (the symbol is put in the middle and the electrons around in shells)

15 Electron Configurations
The arrangement of the electrons in the electron shells can be written as an electron configuration. Looking at the sodium atom below, there are 2 electrons in the first shell, 8 electrons in the second shell, and 1 electron in the third shell. This can be written as: 2, 8, 1

16 How does this relate to the Periodic Table?
Fact 1: Elements in the same group have the same number of electrons in the outer shell (this correspond to their group number) H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Fe Ni Cu Zn Br Kr Ag I Xe Pt Au Hg These elements have __ electrons in their outer shells These elements have __ electrons in their outer shell E.g. all group 1 metals have __ electron in their outer shell

17 How does this relate to the Periodic Table?
Fact 2: As you move down through the periods an extra electron shell is added. E.g. Lithium has 3 electron in the configuration 2,1 H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Fe Ni Cu Zn Br Kr Ag I Xe Pt Au Hg Sodium has 11 electrons in the configuration 2,8,1 Potassium has 19 electrons in the configuration __,__,__

18 How does this relate to the Periodic Table?
Fact 3: (Most important) All of the elements in the same group have similar properties. H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Fe Ni Cu Zn Br Kr Ag I Xe Pt Au Hg E.g. consider the Group I metals. They: Are soft Can be easily cut with a knife React with water


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