1. Ionic vs. Molecular Compounds

2. What is an ion?
Definition: atoms that have lost or gained electrons
Gain electrons (anion) - charged ion
Lose electrons (cation) + charged ion
The number next to the charge indicates how many electrons were lost or gained
Examples:
Sodium (Na)
Neutral atom: Na
Sodium Ion: Na+
Oxygen (O)
Neutral atom: O
Oxygen Ion: O-2
***But how do we determine how many electrons an atom will gain or lose?***

3. How many valence electrons?
Definition: the outermost electrons in a neutral atom’s electron cloud
What do I mean by a neutral atom?
The atom has an equal number of protons and electrons
The group # corresponds to the # of valence electrons
How many valence electrons?
Group 1= 1 Valence electron
Group 2= 2 valence electrons
How many valence electrons does group 3 have?
How many valence electrons does group 7 have?
How many electrons does group 8 have?

4. Lewis Dot Structures
Definition: structures that illustrate the number of valence electrons that an element has.
Steps to drawing Lewis Dot Structures:
Write the symbol of the element. The symbol can be found on the periodic table.
Determine the number of valence electrons in the element.
We use dots to represent valence electrons. Starting above the symbol of the element, draw one dot at a time, in clockwise order, around the symbol.
No more than 2 dots can go on each side of the symbol.
No more than 8 dots can EVER be around a symbol.
When finished, double check that dots are evenly spaced out as far away from each other as possible.

5. Lewis Dot Structures: Examples
Chlorine
Symbol: Cl
Valence electrons: 7
Magnesium
Symbol: Mg
Valence Electrons: 2
Carbon
Symbol: C
Valence electrons: 4

6. Noble Gases and the Octet Rule
Atoms are more stable when they have 8 electrons in their outermost shell.
Which group is the most stable?
The noble gases!
EVERYone wants to be like them!
So, Group 7 has 7 valence electrons.
Does it want to lose 7 or gain 1 electron? (which is less work)
What about the other groups?
Label your periodic table with the charges

7. Molecular vs. Ionic http://www.youtube.com/watch?v=_M9khs87xQ8
Ask: what do you think the difference is?

8. Properties of Molecular & Ionic Compounds
Molecular Compounds:
A molecule is the smallest electrically neutral unit of a substance
Low melting and boiling points
Gases or liquids at room temp
Composed of 2 or more nonmetals
Ex: H2O
Called a molecular formula
Shares electrons
Ionic Compounds:
Composed of ions (+ and -)
Cation= + charge
Anion = - charge
Has gained or lost electrons
Composed of a metal and a nonmetal
Composed of a cation and an anion
Mostly solid at room temp.
Called formula units when combined.
***PROTONS ARE NEVER TRANSFERRED OR EXCHANGED***

9. Naming Ions Cations Anions
Positively charged ions that are caused by a loss of electrons
Named by taking the name of the element and adding “ion”
Examples
Na+: Sodium ion
Mg2+: Magnesium ion
Al3+: Aluminum ion
Anions
Negatively charged ions caused by a gain of electrons
Named by taking the first syllable of the name of the element, adding “- ide”, and then ion
Fl-: Flouride ion
O2-: Oxide ion
N3-: Nitride ion

10. Naming Ionic Compounds
Three types:
Type 1: Monotomic; what does mono stand for?
Ions consisting of only one atom
(these are simple ionic bonds)
Type 2: Polyatomic; What does poly stand for?
Ions consisting of many types of atoms
(These are the ions found on the back of your periodic table)
Look at the back of your periodic table and notice the several types of polyatomic ions
Type 3: Group B elements, or group 4 elements
USE A ROMAN NUMERAL!
What are roman numberals?

11. Type 1: Monotomic FORMULA  NAME Example: NaCl Follow these steps:
Always ask yourself “Is there a metal present?”
Yes- ionic compound
No- molecular compound
How many elements do I have in each of my ions?
Does this example have a group B element, or group 4 element?
How do you name it?

12. Type 1: Monotomic FORMULA  NAME Example: MgBr2
Is there a metal present?
How many elements make up each ion?
Does this example have a group B element, or group 4 element?
How do you name it?

13. Type One: Monotomic NAME  FORMULA
WHEN ELEMENTS FORM A COMPOUND- THEY BECOME NEUTRAL!
Example: Lithium Bromide
What is the charge of lithium?
What is the charge of Bromine?

14. Type one: Monotomic Name  Formula Example: Aluminum Oxide
What is the charge of aluminum?
What is the charge of oxygen?

15. Type 1: Practice
Use an elbow partner to help you write the name or formula for the following compounds:
1) Mg Se
2) Cesium Oxide
3) Gallium Bromide
4) LiBr
5) K2S
6) BaI2

16. Type 2: Polyatomic Formula  Name Example: NaNO3
Why is this polyatomic?
What is Na?
What is NO3? Where can you find it?
Name Na, name NO3
You’re done! 

17. Type 2: Polyatomic Formula  Name Example: NH4CN
Why is this polyatomic?
What is NH4?
What is CN? Where can you find it?
Name NH4, name CN.
You’re done! 

18. Type 2: Polyatomic Name  Formula Example: Calcium Sulfate
Write the cation (+) on the left and the anion ( - ) on the right.
Balance the charges
Use ( ) if needed.

19. Type 2: Polyatomic Name  Formula Example: Magnesium Hydroxide
Write the cation (+) on the left and the anion ( - ) on the right.
Balance the charges
Use ( ) if needed.

20. Type 3: Group B or group 4 Formula  Name Example: CuCl
Why is this type 3?
YOU MUST USE A ROMAN NUMERAL FOR THIS TYPE!
THE ROMAN NUMERAL = THE CHARGE!
Look at the back of your periodic table- find copper under monotomic ions…see it could be copper +1 or copper +2, you must figure out which.
Put the cation (+) on the left and the anion (-) on the right
Which element do you know the charge of?
How many coppers and how many chlorines do you have?
So, what charge does copper have to be?

21. Type 3: Group B, or group 4 Formula  Name Example: Sn2Cl4
Why is this type 3?
What do we need to add to this type? What does this stand for?
Put your cations on the left (you have 2 Sn); anions on the right (you have 4 chlorine’s)
What does tin’s charge have to be?

22. Exceptions Transition metals with only ONE charge
Ag+: silver ion
Cd2+: cadmium ion
Zn2+: zinc ion
Representative elements that CAN have more than one charge (therefore the charge must be indicated in parenthesis)
Lead (Pb)
Tin (Sn)
Antimony (Sb)