1. Chapter 8: Ionic Compounds

2. 8.1: Forming Chemical Bonds
Chemical bond- the force that holds two atoms together
Ionic bonds- exist between oppositely charged ions
Cation- positively charged ion
Anion- negatively charged ion

3. Mini-review
Electron configuration reveals Principle Energy Level where valence electrons are found
Valence electrons are the electrons involved in bonding
Represent valence electrons via electron dot structures

4. Formation of Positive Ions
Positive ions form when atoms lose electrons in order to attain 8 valence electrons (like a noble gas)
Examples:
Na 1s22s22p63s1  1 val. e-
When sodium loses that one electron it assumes a noble gas config. of s2p6
Once it ionizes it then has more protons than electrons and has a charge of +1. (CATIONS)

5. Formation of Negative Ions
Again, atoms want to attain 8 val e-
Example:
Cl: 1s22s22p63s23p5 will gain 1 e- to attain a tot. of 8
When chlorine gains that one electron it assumes a noble gas config. of s2p6
Once it ionizes it then has more electrons than protons and has a charge of -1. (ANIONS)

6. Charge Chart Group 1A  all will form +1 charge
Group 4A  +/- 4 charge
Group 5A  all will form a -3 charge
Group 6A  all will form a -2 charge
Group 7A  all will form a -1 charge
Group 8A  will not form a charge

7. 8.2 Formation of Ionic Bond
Ionic bond- the electrostatic force that holds oppositely charged particles together
Forms between positively charged metal cations and negatively charged non-metal anions.
Example:
Na+1 and Cl-1 becomes NaCl
1s22s22p63s1
3p53s2p62s21s2

8. Also explained via Electron Dot Models

9. Ionic Vocab.
If a metal combines with a non-metal it forms an ionic compound called a salt.
Exception: A metal bonding with oxygen is called an oxide.
Many ionic compounds are binary which mean they consist of two elements.

10. What happens if….
A compound forms from Calcium (Grp. 2A) and Fluorine (Grp. 7A)
Calcium will need to lose _2__ electrons to become stable.
Fluorine will need to gain _1_ electron to become stable.
SO, what happens?
One Ca+2 cation will attract two F-1 anions
CaF2

11. In-class Ex. page 217 7. Sodium and nitrogen 8. lithium and oxygen
9. strontium and fluorine
10. aluminum and sulfur
11. cesium and phosphorus

12. Properties of Ionic Compounds
Crystalline structure
Large amt. of energy required to break bonds
Formation of ionic bonds is always exothermic
Solid state non-conductors
In aqueous solution  great conductors (aka electrolytes)

13. 8.3 Names and Formulas for Ionic Compounds
Formula units
simplest ratio of the ions represented in an ionic compound
Overall charge (net charge) is ZERO
Ex. KBr [one ion of potassium (K) and one ion of Bromine (Br)]

14. Determining Charge
Monotomic ions: charge is equivalent to the group number (Group 1A-Group 8A)
Charge is called its oxidation number
Oxidation state equals the number of electrons transferred from an atom of the element to form the ion.
Transition elements can have more than one oxidation state (see page 222, table 8.5)

15. Polyatomic Ions- ions made up of more than one atom.
The charge on polyatomic ions applies to the entire group of atoms
Acts as an individual ion rather than a group
Ex. NH4+1 and Cl-1
NH4Cl

16. In-Class Ex. Page 224 and Page 225
19. Potassium and iodine
20. magnesium and chlorine
21. aluminum and bromine
22. cesium and nitrogen
23. barium and sulfur
24. Sodium and nitrate
25. Calcium and chlorate
26. Aluminum and carbonate
27. Potassium and chromate
28. Magnesium and carbonate

17. Naming Compounds
With monotomic ions, cations stay the same; however, anions change their ending to –ide
Polyatomic ions:
Most are oxyanions (has oxygen)
Some are composed of exact same ions but in different amounts
The ion with more oxygen ends in -ate
The ion with less oxygen ends in –ite
Ex. NO3-1 nitrate NO2-1 nitrite

18. Chlorine (forms 4 oxyanions)
ClO4-1: perchlorate
ClO3-1:chlorate
ClO2-1: chlorite
ClO-1: hypochlorite

19. Rules in a Nutshell 1. Name cation before anion
2. Monotomic cations use the name
3. Monotomic anions use the root of the name and add –ide
4. Groups 1-2 metals have one oxidation number while transition metals have more than one
5. Polyatomic ions  name them.