Section 4-2

 Usually shiny  Usually hard  Conduct electricity and heat

 Metallic nature appears to be dependent on temperature  Tin can change to a nonmetal under the right conditions  Most nonmetals can be changed to metals at low temps  Least conductive metal conducts electricity 100x better than the best conduction nonmetal

 Copper and Gold have very similar levels of conductivity  Gold is more expensive  Cu is used in home and business electrical wiring  Gold is used in car seatbelts and in airbags  Gold and copper is used in computers  Al was used in home but its higher corrosion level made it a hazard

 Electrons are responsible for the transfer of heat  Electron configuration of metals are different from the electron configuration of nonmetals  Electrons in metals are able to move more freely through the atom

 Crystals – atoms and/or molecules that have a repeating 3D geometric pattern  Electrons of one atom will help to form bonds with other atoms  e- in higher orbitals than the ground state are free to move through the crystal  Conduction band – a region within which e- must move to allow electrical conduction  Due to thermal motion at room temp if the temp increase it will not allow the e- to move as freely between atoms

 Semiconductors - these are nonmetals which at certain temperature will act like metals  With more heat we can have a similar thermal motion to that of metals  This overlap the conduction band and allows these element to act like metals and conduct electricity

 Just because a metal is a good conductor of heat doesn’t mean it is a good conductor of electricity  Diamonds conduct heat but not electricity  High thermal conductivity explains why metals are cold to the touch  The heat from your fingers gets sucked away from your fingers in to the metal

 Variety of melting points  Different states of mater  Reactivity  How one element will react with others  Cs – “explodes” in water (violent reaction)  Variety of strengths  Ductility – pulled into wire  Malleable – hammered and rolled into sheets

 Alloy – combination of two or more metals  Adds to the versatility  Sometimes prevent corrosion

 Metallic atoms can form crystals  Diamonds, salt and sugar just to name few  Cubic-close packed structure or Face-centered cubic – if the atoms in each layer are placed directly above the spaces in the previous layer  Hexagonal crystal – when the third layer of the structure is directly over the first layer  Other shapes are formed from bonds that force the atoms into a crystal

 Some elements exist as diatoms  H 2, N 2, O 2  The subscript indicates how many atoms are in the molecule  Metals can exist in structures of many atoms and when cut in half still retain the same properties but with half the atoms.  We write these as monatomic symbols but the only true monatoms are noble gases