1. Chapter 7: Ionic and Metallic Bonding
Honors Chemistry
Chapter 7: Ionic and Metallic Bonding

2. Ions Valence electrons
“A” group: number of groups = number of valence electrons
Transition metals: need more information: either Roman numeral designation of oxidation state, -ic or –ous if only two oxidation states (-ic is for larger #)
Octet Rule: atoms either gain or lose electrons so as to reach the electron configuration of a noble gas
Cations: loss of electrons to reach the noble gas configuration; typical of elements with 1, 2 or 3 valence electrons
Anions: gain of electrons to reach the noble gas configuration; typical of elements with 5, 6, or 7 valence electrons
Elements with 4 valence electrons typically bond covalently
Elements with 8 valence electrons typically do not bond

3. Ionic bonds and ionic compounds
Formation of ionic compounds
Ionic bonds: # positive charges must equal # negative charges…development of appropriate subscripts for compounds comes from this…criss-cross should help arrive at correct number, assuming correct charge is listed (see previous slide!)
Formula unit: the lowest number of ions in the correct whole number ratio…realization is that ionic compounds form network solids rather than simple molecules…consider illustration, pg. 195, of sodium chloride
Properties of ionic compounds
Crystalline solids, typically, as have higher MPs
When molten or dissolved in water (if soluble), will conduct an electric current
Coordination number: number of ions of opposite charge that surround an ion in a crystal (see page 198)

4. Bonding in Metals
Realization that metals can be modeled as being in a sea of relatively mobile electrons
Metallic bonds, then, are the bonds of these “flowing” electrons, creating some degree of attraction between atoms
This also explains the characteristics we expect and see from metals
Malleability
Ductility
Electrical/thermal conductivity
Alloys
Mixtures of two or more elements, at least one metal
Like any hybrid, there are particular properties that are superior to the components