27 - metal. The underlying atoms have a net positive charge...

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Bonding -Material properties depend on the type of bonding that hodls the atoms together in that material. Examine the forces as 2 atoms are brought together -force=when 2 atoms are far apart big slope- stiff material (high modulus) -slope is related to the stiffness of material -graph is for 2 atoms, real materials have more complicated graphs that depend on direction. -the area under the curve is equal to energy Types of Bonding 3 main types 1. Metallic-metals 2. Ionic-ceramics 3. Covalent-polymers Metallic Bonding -In metals a few electronic (negatively charged) from each atom are only loosely bonded to that atom and form a sea of free electrons that are free to drift around throughout the
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Unformatted text preview: metal. The underlying atoms have a net positive charge due to the loss of a few electrons to the electron sea. It results in good electrical conductivity for metals and metallic lustre Ionic Bonding Found in materials that typically come a metal with a non metal. Ceramics Metal: sodium, potassium, iron all give up electrons Nonmetal:-chlorine, bromine,oxygen, nitrogen all accept electrons Covalent bonds can be weak or strong Directionality has important implications for properties. Polymers have covalent bonds and polymer chains can be very strong along the backbone of the chain...
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This document was uploaded on 10/17/2011.

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