2. Major Bond Types COVALENT e- are shared between 2 atoms
IONIC
e- are transferred from one atom to another
COVALENT
e- are shared between 2 atoms

3. Formed between a metal and non-metal Formed between 2 non-metals
When does it occur?
IONIC
Formed between a metal and non-metal
COVALENT
Formed between 2 non-metals

4. How does it hold atoms together?
COVALENT
Shared attraction for same e- (+nucleus pulls on e-)
Polar: doesn’t share equally
Nonpolar: shares equally
IONIC
Electromagnetic forces;
cation/ anion (opposites attract)

6. "GENEROUS"
NON-METALS
METALS
"GREEDY"
with their electrons

7. What is an example?
IONIC
COVALENT

8. How to draw an Ionic Bond
1. Write the elements that you are combining

9. 2. Do a Lewis Dot Diagram for each atom

10. 3. Draw the arrow from the e- that are moving to their new location
3. Draw the arrow from the e- that are moving to their new location. Add the final molecule on the right side (don’t forget the charges)

11. How to draw a covalent bond
1. Draw the Lewis Dot Diagram of each atom

12. 2. Put the pieces together like a puzzle.
Recall: the goal is to get a full valence shell

13. Ionic Compounds (salts)
Made up of
positive and negative ions
cations and anions
a metal and a nonmetal
Smallest repeating unit- formula unit

14. Properties of Ionic Compounds
All are Crystalline solids -
They have a regular repeating arrangement of ions in a rigid 3-D structure
Ionic bonds are the strongest bonds, so these compounds have high melting points

15. Properties of Ionic Compounds
This orderly arrangement of component ions produces the beauty of crystalline solids.
The beauty of crystalline solids, such as these, comes from the orderly arrangement of their component ions.

16. More properties of ionic compounds
Conducting electricity is allowing charges (electrons) to move.
In a crystalline solid, the ions are locked in place so they can’t conduct electricity
When melted or dissolved in water, the ions are free to move around and, therefore, conduct electricity
Brittle solids at room temperature

17. Properties of Ionic Compounds
Summary:
Properties of Ionic Compounds
Structure:
Crystalline solids
Melting point:
Generally high
Boiling Point:
Electrical Conductivity:
Excellent conductors, when molten and aqueous
Solubility in water:
Generally soluble

18. Properties of Molecular (Covalent) Compounds
Tend to have low melting and boiling points
Poor or nonconducting
Have a molecular formula which shows type and number of atoms in a molecule
Not necessarily the lowest ratio!
Ex. C6H12O6
(Formula doesn’t tell you about how atoms are arranged)

19. Bond type by electronegativity
Electronegativities are listed on pg 151
Difference Bond Type
< nonpolar covalent
between 0.4 and 2.0 polar covalent
> ionic

20. Bond Polarity Examples: Cl2 HCl 3.0-3.0=0.0 Nonpolar 3.0-2.1=0.9 NaCl
=2.1
Ionic
We should guess this because it’s 2 like atoms
We should guess this because it’s 2 different non-metals
We should guess this because it’s a metal & a non-metal