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Unformatted text preview: Material types • Metal+ Alloys, Crematics + Glass, Semi-Conductors, Polymers, Composites Valence-Determined by the number of electrons in the outer most electron shell Atomic Number (Z) -number of protons in each atom Atomic Mass (A) -also called atomic weight, sum of the masses of protons and neutrons in the nucleus Avogadro’s Number (NA) 6.023 X 10 23 atoms/mole Electronegativity -The tendency of an atom to accept valence electrons, EN increases from left to right, bottom-top Primary Bonding- (electrons shared, transferred), Strong • Ionic Bonding- Occurs between + and –ions, Requires electron transfer, Large difference in electronegativity required,Example: NaCl • Covelent bonding- Requires shared electrons, Example: CH4,Covalently bonded materials form specific bonding angles depending on the material • Metallic Bond- Arises from a sea of donated valence electrons(1, 2, or 3 from each atom), Valence electrons are not bound to any particular atom, Primary bond for metals and their alloys, Good conductors of heat and electricity because of...
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This note was uploaded on 04/17/2008 for the course MNUF 203 taught by Professor Fred during the Spring '08 term at Wisc Stout.
- Spring '08