1. 5 Metallic bonding

2. Metallic bond Occurs between metal atoms Metal atoms pack close together.

3. Many metals have an unfilled outer orbital In an effort to be energy stable, their outer electrons become delocalised amongst all atoms No electron belongs to one atom They move around throughout the piece of metal. Metallic bonds are not ions, but nuclei with moving electrons

4. Metallic Bonding  The chemical bonding that results from the attraction between metal cations and the surrounding sea of electrons  Vacant p and d orbitals in metal's outer energy levels overlap, and allow outer electrons to move freely throughout the metal  Valence electrons do not belong to any one atom

5. Physical Properties Conductivity Delocalised electrons are free to move so when a potential difference is applied they can carry the current along Mobile electrons also mean they can transfer heat well

6. Malleability The electrons are attracted to the nuclei and are moving around constantly. The layers of the metal atoms can easily slide past each other without the need to break the bonds in the metal

7. Melting/Boiling points High energy is required for the cations and its electrons to break away so BP/MP are very high.

8. Shiny Light reflected by the mobile electrons causes metals to shine..

9. Impurities and Melting points An impurity disrupts the regular lattice that its particle adopts in the solid state, so it weakens the bonding.  They always LOWER melting points  Its often used to check purity of a known molecular covalent compound.

10. Properties of Metals  Metals are good conductors of heat and electricity  Metals are malleable  Metals are ductile  Metals have high tensile strength  Metals have luster

11. Modifying metals

12. Alloys Alloying one metal with other metal(s) or non metal(s) often enhances its properties  Steel is stronger than pure iron because the carbon prevents the delocalised electrons to move so readily.  If too much carbon is added then the metal is brittle. They are generally less malleable and ductile Some alloys are made by melting and mixing two or more metals  Bronze = copper and zinc  Steel = iron and carbon (usually)

13. CA Standards Students know atoms combine to form molecules by sharing electrons to form covalent or metallic bonds or by exchanging electrons to form ionic bonds.