**IONIC BONDS Only certain ratios (combinations) of elements result in the formation of Ionic...

**IONIC BONDSOnly certain ratios (combinations) of

elements result in the formation of Ionic compounds.

For ex: Lithium (Li) will react with Fluorine (F) to form LiF.

BUT, it will NOT form LiF2, LiF3, etc.

Magnesium (Mg) will react with Fluorine to form MgF2.

BUT, it will NOT form MgF, MgF3, etc.

**Warm up Questions Without using your notes, answer the following

questions. Write the questions!1. What is a compound?

Two or more DIFFERENT atoms (elements) that are chemically bonded together because of a chemical reaction.

2. Which formula is a compound and why?C8H10N4O2 or F2

C8H10N4O2= compound3. What are the element(s) that make up each

chemical formula in question 2?Carbon, Hydrogen, Nitrogen, Oxygen

Fluorine

IONIC BONDS• What could you do to get the charges

to cancel out if you wanted to form this ionic compound???

Li+1 + O-2

ANSWER: You would need to use 2 Li+1 for every O-2!!!= Li2O

**Getting Connected

Element 1(metal)

# of valence e-

Element 2(nonmetal

)

# of valence e-

Compound Name

and chem.

formula

Total # of valence e-

Na 1 F 7 NaF 8

COVALENT BONDS• Form between two non-metals or

between molecules.

• Bond because the outer electron rings are not full so they share valence e-

• **Form by sharing valence electrons

• (The atoms are NOT stable.)

Properties of COVALENT BONDS

• These are weak bonds.

• Covalent compounds will have low melting and boiling points.

• Some examples are H2O (water/ wudder), and

CO2 (Carbon Dioxide)

COVALENT BONDS• The reason H2O is covalent:

Remember H can be a metal or a non-metal!!!

Here H is behaving like a non-metal. Hydrogen is usually a non-metal!

Let’s Practice!Write the following compounds and determine if

they are Ionic or Covalent?

1.) NH3 7.) BeO

2.) NaCl 8.) P2O5

3.) CH4 9.) Li3P

4.) CO2 10.) BN

5.) CaCl2 11.) N2O

6.) KBr 12.) MgS

ANSWERS…1.) NH3 Covalent 2.) NaCl Ionic 3.) CH4 Covalent 4.) CO2 Covalent 5.) CaCl2 Ionic 6.) KBr Ionic

7.) AlCl3 Ionic

8.) P2O5 Covalent

9.) Li3P Ionic

10.) BN Covalent

11.) N2O Covalent

12.) MgS Ionic

Covalent vs. Ionic(Four Corners)

covalent 2 non-metals

share val. e- ions w/ opposite charges

weak bonds 1000C (low) boiling pts.

ionicmetal and nonmetaltransferring val. e’strong bonds14650C (high) boiling

pts.

Lewis Structures Electron Dot Diagrams

• We will show how the atoms share electrons by drawing electron dot diagrams.

• You will only use the valence e- for dot diagrams.

Dot Diagrams

• Start the dot diagram by writing the atomic symbol for the atom.

Ex: Mg

The symbol has 4 sides…

Dot Diagrams

Mg

Each side can hold up to 2e-

You cannot pair the electrons until there is one on each side.

Dot Diagrams

Mg

Mg only has 2 valence e-.

So it’s dot diagram looks like this: Mg Let’s try… Si

how about… S

Dot Diagrams Practice!!! Draw the Dot Diagrams for:

a) Cl b) Cc) Al d) Nee) Na f) N

Dot Diagrams

How did you do???

a) Cl b) C

c) Al d.) Ne

e.) Na f.) N

Dot Diagrams Practice Problems

1. K2. Sr3. B4. Si5. P6. S7. Kr8. Ca9. O

Dot Diagrams

Now we can put individual diagrams together to show whether atoms transfer or share their valence e-!!!

Dot Diagrams for Ionic Bonds

We know that in an Ionic Bond atoms are transferring their valence e- …

We use a arrows between the Atomic Symbols to represent the transferring of e-.

We can show this w/ dot diagrams. For Ex: (Li + Cl = LiCl) Cl Li

**Dot Diagram Practice for Ionic Bonds

1.BeO2.NaCl3.MgS4.CaCl2

5.Li3P

6.AlCl3