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METALS

METALS. Bonds and Properties. Alloys Pure Elements. LUSTER. HIGH. DEFORMABILITY. Malleable & Ductile. CONDUCTIVITY : HEAT AND ELECTRICITY. Good to Excellent. PHASE at STP. Solid (except Hg). Ion FORMATION. Lose e - to form (+) ions. IONIZATION ENERGY. Low (lowest: Fr).

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METALS

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  1. METALS Bonds and Properties Alloys Pure Elements

  2. LUSTER HIGH DEFORMABILITY Malleable & Ductile CONDUCTIVITY : HEAT AND ELECTRICITY Good to Excellent PHASE at STP Solid (except Hg) Ion FORMATION Lose e- to form (+) ions IONIZATION ENERGY Low (lowest: Fr) ELECTRONEGATIVITY Low (lowest: Fr) Some Properties of Metals

  3. Many metals have high luster Hmmm…. How much is this shiney Gold worth !? 400 ounces (27.5lbs) $1738.35 / ounce $695,340.00 per bar 12 bars = $8,344,080.00

  4. Many Metals have high melting points

  5. Metallic bonding: different from ionic bond Both bond types due to: electrostatic attraction Ionic bond: transfer electrons from one atom to another Metal bonds: electronsROAM FREELYfrom one metal atom to next • sea of mobile electrons • accounts for properties of metals Metal bonding

  6. Why can electrons in metals roam freely about?

  7. Metal bonding • Metals: form organized lattice structures similar to ionic cmpds • adjacent atoms in metal lattice are all same • close proximity of atoms allows outer energy levels to overlap So…

  8. electrons in outer valence shell can move freely through these overlapping energy levels = “sea of mobile electrons”

  9. Na 1s1 Na 1s1 Overlapping orbitals

  10. Metal bonding • Freely moving electrons: • called “delocalized” electrons • allows (+) metal cation to form • Delocalized electrons move freely throughout metal from one cation to next • creates what’s called “the sea of mobile electrons”

  11. This sea of electrons: • binds each metal cation to each • neighbor cation • this creates the metal bond

  12. sea of mobile electrons gives metals some of their unique properties since electrons move freely from place to place they: • conduct electricity (a flow of electrons) • conduct heat • are malleable and ductile • have luster How do electrons do this? Metal Properties

  13. Electrical Conductivity - + Flow of electrons e-   e- Free flow of electrons through the metal e- flow from metal through metal wire towards (+) charge; then flow from (-) terminal back into metal

  14. Metals & non-metals behave very differently when hit with a force such as hammer Metals DEFORM: Non-metals SHATTER Why? Metals have free flowing electrons & nonmetals do not! Malleability

  15. Metal Non-Metal If force applied to metal: • some metal atoms shift away from force & free electrons simply bond the newly overlapping metal ions together • metal is deformed but shift doesn't change metal atoms If force applied to non-metal: • like charges align (+) & (+) (-) & (-) which results in shattering due to force of repulsion

  16. Deformation of Metals Deformation of Metals

  17. As # of electrons that can be delocalized ↑ so does: Hardness and Strength Na has one valence electron that can be delocalized so: - is relatively soft ( can be cut with a butter knife) Mg has two electrons that can be delocalized so: - can still be cut but is much harder than Na Transition metals have varied # of e-'s that can be delocalized - Chromium is very hard and has high strength

  18. Alloys • mixture of elements that have metallic properties • mixture can be adjusted to get desired properties • can be substitutional or interstitial • element sizes same size or different sizes

  19. Common alloys Brass: Cu & Zn Bronze: Cu, Sn & Al Pewter: Sn, Pb & Cu Solder: Pb & Sn Rose gold: Cu & Al White gold: Au & Ni, Pd or Pt Sterling silver: Ag & Cu Steel: C & Fe Stainless steel: Cr & Ni

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