1. CHEMISTRY
October 19th, 2011

2. Welcome Back! October 19th, 2011
Brainteaser:
Let’s reflect on last quarter’s performance:
What are some things you thought you did well for this class?
What are some things you think you could improve for this quarter?
What is your overall goal for this quarter (i.e. what do you want to accomplish this quarter and how are you going to do it?)

3. Agenda Brainteaser Unit 5: Ionic Bonding Notes Homework
Ionic Bonding Practice Worksheet

4. Unit 4: Chemical Bonding
Differences in chemical behavior are due to differences in the types of bonds
Bond: forces that hold atoms together in molecules or ionic compounds.

5. Chemical Bonding Types of bonds and types of substances Ionic Covalent
Metallic
The type of bond between atoms is partially responsible for the properties of the substance.

6. Chemical Bonding Bonding
Involves the valence electrons or outermost shell (or highest shell) electrons
For group A elements – the group number tells how many valence electrons
For example:
K, Ca, C, B, N, F, Ne
Lewis Dot Structures show the valence electrons around an atom and for most molecules and compounds a complete octet for the elements is needed.
For example: N, Al, H2O

7. Lewis Dot Structures These symbols are called Lewis symbols 
We generally place the electrons on four sides of a square around the element symbol.

8. Drawing Lewis Dot Structure
Place DOTS around the SYMBOL clockwise pairing up dots on the second time around
For example:
Magnesium (Mg) and Oxygen (O)  MgO Mg O

9. Ionic Bonding

10. Ions and Ionic Compounds
Ions are formed by adding or subtracting electrons from a neutral atom or molecule.
Cation: positively charged ions (remove e-)
Anions: negatively charged ions (add e-)

11. Two Types of Ions Monatomic ions Polyatomic ions Single atom ions
Al3+
Polyatomic ions
More than one atom ions
NH4 +
OH –
SO4 2-

12. Predicting Charges of Ions
Electron Counts of Stable Ions
Ions tend to have the same number of electrons as the nearest noble gas.
Transition metals are not as predictable, but +2 and +3 are common.

13. Main Group Elements
Note periodicity of charges

14. Transition Elements
Not periodic; +2 and +3 common

15. Charges and Formulas of Oxoanions
Oxoanions generally have the same charge as the simple anion of the same nonmetal.
Related to position in the periodic table; note exceptions for B, C, N
Polyatomic Ions
tend to reflect
the charge of the base element

16. Ionic Bonds form when… A cation (metal) bonds with an anion (nonmetal)
A salt is formed:
For example: Sodium: Na “metal” bonded to Chlorine: Cl “nonmetal”
For example: Magnesium: Mg “metal” bonded to Chlorine: Cl “nonmetal”

17. Ionic Bonding: The Formation of Sodium Chloride
Sodium has 1 valence electron
Chlorine has 7 valence electrons
An electron transferred gives
each an octet
Na: 1s22s22p63s1
Cl: 1s22s22p63s23p5

18. Ionic Bonding: The Formation of Sodium Chloride
This transfer forms ions, each with an octet:
Na+ 1s22s22p6
Cl- 1s22s22p63s23p6

19. The resulting ions come together due to electrostatic attraction
(opposites attract):
The resulting ions come together due to electrostatic attraction
(opposites attract):
The resulting ions come together due to electrostatic attraction
(opposites attract):
The resulting ions come together due to electrostatic attraction
(opposites attract):
Na+
Cl-
Na+
Na+
Cl-
The net charge on the compound must equal zero
The net charge on the compound must equal zero

20. Lewis Dot Drawing
Ionic bond
Example
Lewis Dot diagram
A positively charged ion is attracted to a negatively charged ion.
A transfer of electrons
Metal and a Non-Metal
NaCl
A positively charged ion is attracted to a negatively charged ion.
A transfer of electrons
Metal and a Non-Metal
NaCl
A positively charged ion is attracted to a negatively charged ion.
A transfer of electrons
Metal and a Non-Metal
NaCl Na Cl

21. Practice Draw the Lewis dot structures for the following compounds:
CaO
BaCl2
Na2S

22. Writing Formulas for Ionic Compounds
Crisscross Method
Example:
Ca and F
Write the element symbols for the cation and anion, with the cation on the left and the anion on the right.
Write each ion’s charge as a superscript.
Crisscross the two charges moving them downward diagonally from one superscript to the other subscript.

23. Practice
Write the correct formula for the ionic compounds composed of the following pairs of ions using the crisscross method:
Potassium and iodide
Magnesium and chloride
Aluminum and bromide
Cesium and nitride
Barium and sulfide
Iron (II) and fluoride

24. CHEMISTRY
October 20th, 2011

25. Warm Up Write the correct formula for these ionic compounds:
Aluminum oxide
Barium nitride
Iron (III) oxide
Magnesium carbide

26. Agenda Brainteaser Grade Homework: Practice W/S Unit 5 Notes:
Naming Ionic Compounds
Properties of Ionic Compounds
Partner Bonding Activity
Homework:
Naming Ionic bonds W/S

27. Naming Ionic Compounds
Step 1:
Cation is written first in the name; anion is written second in the name
Name of cation is the same as the neutral atom element (Na+ = Sodium)
Step 2:
Anion is written by adding the suffix –ide to the root of the element name (I- = iodide)
For example: NaCl = Sodium Chloride, Al2O3 = Aluminum oxide
Step 3:
Figure out if you need a Roman numeral in the name (transition metals).
Figure out what the Roman numeral should be
For example: Fe2O3
Step Four: Check your work

28. Practice Naming Ionic CompoundsKF
AlF3
KCl
Na3P
Fe2O3

29. Properties of Ionic Bonding
Definition:
In an ionic bond, a positively charged ion is attracted to a negatively charged ion
Electrostatic Attraction

30. Properties of Ionic Bonding
Solid at room temperature
Electrical conductivity
Conducts electricity when dissolved in water or in liquid (molten) form
Dissociated ions can carry charge through the solution
Hardness
Hard but brittle
Electrostatic repulsion
Melting points and Boiling points
High melting and boiling point
Forces of attraction between positive and negative ions are strong

31. Properties of Ionic Bonding

32. Quiz Write the chemical formula for these ionic compounds:
Sodium bromide
Potassium nitride
Beryllium phosphide
Write the chemical names for these ionic compounds
SrCl2
MgI2
Ba3N2