METALS Bonds and Properties Alloys Pure Elements

Hmmm…. How much is this shiney Gold worth !? 400 ounces (27.5lbs) Many metals have high luster Hmmm…. How much is this shiney Gold worth !? 400 ounces (27.5lbs) $ 1183.00/ ounce $473,200.00 per bar 12 bars = $5,678,400.00

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 electron energy levels to overlap So…

Na 3s1 Na 3s1 overlapping valence electron orbitals

electrons in outer valence shell can move freely through these overlapping energy levels: results in “sea of mobile electrons” allows (+) metal cation to form

sea of electrons: binds each metal cation to neighboring cation this creates the metal bond: due to electrostatic attraction between (+) metal cations & sea (-) electrons

Metal Properties How do electrons do this? sea of mobile electrons gives metals their unique properties since e- move freely from place to place metals can: conduct electricity (flow of electrons) conduct heat account for being: malleable ductile shiney (luster) How do electrons do this?

most metals have high melting points large amount of energy needed to overcome both IMF and strong bonding forces of metals in order to change phase

- + Electrical Conductivity e- flow through metal: Flow of electrons e- flow through metal: e- travel through wire from battery, through metal and return to (+) terminal of battery free flowing e- will travel through metal due to attraction of (+) metal cations

If apply force to structure of metals: metal atoms shift away from force & free electrons bond newly overlapping metal cations together metal’s shape is deformed but shift doesn't separate metal atoms If apply force to structure of ionic compounds: forces like charges to align (+) to (+) & (-) to (-) resulting in shattering due to repulsion forces Metal Non-Metal

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 valence electrons that can be delocalized so: - still can be cut but is much harder than Na transition metals have varied # of e-'s that can be delocalized - chromium (Cr+6) is very hard and has high strength

Alloys mixture of elements with metallic properties mixture can be adjusted to get desired properties two types: substitutional and interstitial alloy (depends on size of elements – same or different size)

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