Ionic compounds made up of positive and negative ions, but overall neutral Consist of a metal and nonmetal Also can include polyatomic ions which is a charged compound Crystalline solids at room temperature Strong bonds due to attraction of neighbor ions and reduction of repulsions NaCl has a melting point of 8000C!

Ionic bonds Opposite charges of anions and cations attract each other one or more atoms lose electrons and one or more atoms gain those electrons Criss-cross the charges as new subscripts Simplify subscripts by common denominator if possible

Ionic Bond Examples Sodium forms Na1+ Chlorine forms Cl1- sodium (Na) and Chlorine (Cl) react to form sodium chloride (NaCl, aka table salt) Sodium forms Na1+ Chlorine forms Cl1- Na1++Cl1-  Na1Cl1  NaCl

Ionic bond example #2 Aluminum (Al) and Bromine (Br) react to form Aluminum bromide (AlBr3) Aluminum forms Al3+ Bromine forms Br1- Al3++Br1-  Al1Br3  AlBr3

Metallic Bonds Closely packed cations and loosely held valence electrons Think sea of valence electrons for pure metal (mobile and drifting free) Think fruit at a grocery store Good conductors of electric current (electrons moving freely) Metal can be shaped (pushed into wire form without breaking)

Alloys Combination of two or more elements with at least one being a metal Superior properties of individual elements Harder and more durable, but easier to shape Ex bronze, sterling silver