1. Ch 5 Ions and Ionic Compounds
What is the difference between an atom and an ion?
How can an atom become and ion?
Why do chemists call table salt sodium chloride?
Why do chemists write the formula for sodium chloride as NaCl?

2. Simple Ions
Chemical reactivity – differs based on electron configuration
Noble gases - least reactive, complete outer energy levels
Octet rule – other elements match s and p electron config of noble gases
Alkali metals and Halogens most reactive one electron away from noble config

3. Valence Electrons Periodic table has valence electrons config
Atoms gain or lose electrons to become ions -become charged
Cation has a positive charge loses electrons
Anion has a negative charge gains electrons

4. Some ions with noble gas configs –p162

5. Ions that do not have noble gas configs
Transition metals form ions without complete octets
Most form more than one type of ion

6. Atoms and ions Properties differ
Sodium chloride form Na+ and Cl- in water both very different properties from atoms

7. Ionic Bonding and Salts
bond formed by the attraction between oppositely charged ions
cations(+) and anions(-)
opposite charges attract
One atom is strong enough to pull an electron away from another atom and keep it. This creates the ions which are then attracted to each other. + -

8. Transferring Electrons
Energy is required to transfer electrons
Forming a salt is exothermic and endothermic
Formation of ions endothermic
Formation of solid from ions is exothermic

9. Formation of Sodium Chloride

10. Ionic Compounds Ionic compounds do not consist of molecules
Ionic bonds are strong
Bonding between metals and non-metal
Metal atoms have a low number of valence electrons and a low electronegativity.
Non-metal atoms have numerous valence electrons.
If the electron clouds overlap (bond)..

11. Metals lose valence electrons achieve a stable valence shell
Metals    lose valence electrons    achieve a stable valence shell (usually 8 e-)    gains a positive charge, ie a positive ion. The charge is the number of valence e- it has to lose
Non-metals gain valence electrons achieve a stable valence shell (usually 8 e-)

12. Characteristics of Ionic Compounds
Crystalline solids at room temperature hard and brittle
Have higher melting points and boiling points compared to covalent compounds
Conduct electrical current in molten(liquid) or solution state
Are extremely polar bonds
Most are soluble in water but not soluble in non-polar solvents

13. Sodium Chloride in Three Phases

14. Salt Crystals Arranged in crystal lattice
Crystal structure depends on size and ration of ions
Smallest repeating unit is a unit cell
                        
Calcite
Fluorite
Halite

15. Naming Ionic Compounds
Simple Cations -name of the element
Cu+ copper (I) Cu2+ copper(II)
Simple Anions – name of the element ends in –ide
Cl- chloride
Binary compounds- name of cation plus name of anion
CuCl2 Copper (II) chloride

16. Writing Ionic Formulas
No overall charges
Ion charges must balance
Iron (III)oxide
Fe 3+ O2-
2 x Fe3+ = x O2- = 6-
(6+) + (6-) = 0
Fe2O3
Fe 3+ O2-
Fe2O3

17. Naming polyatomic ions
Ions made of two or more atoms
Charged group
Table on p 178
-ite -ate have oxygen in them
K2CO3
K+ potassium CO32- carbonate
Potassium carbonate