Metallic bonding occurs when metal atoms bond through delocalized electrons. Metals form a lattice structure with positive metal ions surrounded by a sea of delocalized electrons that are attracted to the positive ions. This bonding allows metals to have distinctive physical and chemical properties including malleability, conductivity, and high melting points. Metallic bonding is important for creating alloys and is found in many materials used in daily life.

1. metallic bonding Done by: Zhu Zehao 2A234

2. Contents Introduction Definition Structure Delocalized Electrons Electrostatic Attraction Physical Properties Chemical Properties Commercial usage Daily usage

3. Introduction Metals do not form covalent bonds with each other as they do not have enough valence electrons to achieve a stable octet state. Therefore, there is a special way for metals to bond with each other which is metallic bonding.

4. Definition of metallic bonding Bonding within metals due to the electrical attraction of positively charged metal ions for mobile electrons that belong to the metal crystal as a whole.

5. Structure of metallic bonded metals A lattice of closely-packed positive metal ions surrounded by a “sea” of delocalized valence electrons. Electrostatic attraction of the positive ions for the negatively charged “sea” of electrons is strong. 3D image of metallic bonding in sodium (Na).

6. Delocalized Electrons Electrons in a molecule or solid metal that are not associated with a single atom or one covalent bond. - - - - - - - - - - The diagram above depicts a cloud of delocalized electrons(represented ‘-’)

7. Electrostatic Attraction The force of attraction between ions of different charges which holds the two ions together in a bond. - + Attraction A diagram showing electrostatic attraction between a cation(represented by ‘+’)and an anion(represented by ‘-’).

8. Physical Properties of metallic-bonded metals(in general) Malleability (ability to be flattened without breaking) Ductility (ability to be drawn into wires) Opaqueness Metal luster (shiny)

9. Chemical Properties of metallic-bonded metals(in general) Good heat conductors Electrical conductors Posses high melting points Posses freezing points Posses high boiling points

10. Commercial use of metallic bonding Creating alloys with more desirable physical and/or chemical properties (may or may not require the addition of non-metals.) E.g. Brass and Bronze. Creation of super alloys (may require adding non-metals.) E.g. Hastelloy, Inconel and Waspaloy.

11. Usage of metallic-bonded materials in our daily lives

12. Usage of metallic-bonded materials in our daily lives(Cont.)

13. References http://dl.clackamas.cc.or.us/ch104-08/metallic.htm http://sixthsense.osfc.ac.uk/chemistry/bonding/metallic.asp IGCSE CHEMISTRY DEFINITIONS http://www.youtube.com/watch?v=vTJ4WUIFyV0 http://www.chemistry.wustl.edu/~courses/genchem/Tutorials/LED/weakcovalent.htm http://www.buzzle.com/articles/metallic-bonding.html

14. Picture Sources http://www.chemistry.wustl.edu/~courses/genchem/Tutorials/LED/weakcovalent.htm http://www.google.com.sg/imglanding?q=rockets&hl=en&gbv=2&tbm=isch&tbnid=xuGy1HJEKx8sbM:&imgrefurl=http://blog.al.com/space-news/2009/05/space_shuttle_replacement_ares.html&imgurl=http://blog.al.com/space-news/2009/05/156335main_Orion_launch.jpg&w=2840&h=1615&ei=IxHNTen6LIW-sAPjjemvCw&zoom=1&iact=hc&page=7&tbnh=156&tbnw=231&start=124&ndsp=19&ved=1t:429,r:4,s:124&biw=1366&bih=659

15. Thank You!!