Upload
gordon-anderson
View
217
Download
2
Embed Size (px)
Citation preview
**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