Vocabulary 14
•
•
•
•
•
organic
hydrocarbon
alkane
alkene
alkyne
•
•
•
•
•
ubiquitous
woolgathering
sophistry
meretricious
sylvan
Difference in all of the bonds…
Ionic
Polar Covalent
Non-Polar
Covalent
1.7  4.0
0.3  1.7
0  0.3
High melting
point
Low melting
point
Low melting point
Solids
Solids and
liquids
Liquids and
gases
No dipoles
Dipoles
No dipoles
Dissolves in
Dissolves in
Dissolve in nonpolar covalent polar covalent polar covalent
“Like dissolves like”
• Ionic substances will dissolve in polar covalent
because both contain charges
• Think NaCl and H2O
– NaCl = 3.0 – 0.9 = 2.1 = ionic
– H2O = 3.5 – 2.1 = 1.4 = polar covalent
“Like dissolves like”
• Polar and non-polar will not mix
• Non-polar contains no charges
to attract polar molecules
• Think water and oil
– H2O = 3.5 – 2.1 = 1.4 = polar
covalent
– Oil = non-polar covalent
“Like dissolves like”
• When would this come in handy?
“Like dissolves like”
• Sugar = polar
• Water = polar
“Like dissolves like”
• Gasoline = non-polar Ionic
• Oil = non-polar
Ionic
Polar
Soluble
NonPolar
Not
Soluble
Polar
Polar
Soluble
Polar
NonPolar
Not
Soluble
NonPolar
NonPolar
Soluble
•
worksheet
Lab: Covalent Bonds
• Predict Bond Type
4.0  1.7
1.7  0.3
0.3  0
Ionic
Polar Covalent
Non-polar Covalent
Add this table to the front page of your lab…
Test Tube
Sugar Soluble
(yes/no)
1 (water)
2 (water)
---------------------
3 (alcohol)
4 (alcohol)
Mineral Oil
Soluble (yes/no)
-----------------------------------------
---------------------
1
1
1
2
2
2
3
3
3
4
4
4
5
5
5
6
6
6
Well plate
Test conductivity
Test solubility in water
Test solubility in alcohol
Test Tubes
1
2
•distilled
water
•distilled
water
•sugar
•Mineral
oil
3
•alcohol
•sugar
4
•alcohol
•Mineral
oil
Quiz Thursday!!
• Make sure you know…
– Electronegativity
– Covalent bond strength
– What creates polar and non-polar bonds?
• Unequal or equal sharing?
– Be able to calculate electronegativity
difference and predict bond type
– Solubility of bond types
– Naming ionic and covalent bonds
Lewis Dot Structures
• Used to predict and show structural
arrangement of molecules
• Follows OCTET RULE
• For example PH3
– Phosphorus has 5 valence electrons
– Hydrogen has 1 valence electrons
Lewis Dot Structures
• Hydrogen only has one electron to
share terminal atom (on the end)
• All atoms have full outer energy level (2 or
8 electrons)
Lewis Dot Structures
• Another technique is to substitute lines for
electrons
Lewis Dot Structure Practice
• H2
H H H—H
• H2O
– H = 1 valence e– O = 6 valence e-
H O H
H—O—H
• CCl4
More practice…
– C has 4 valence e– Cl has 7 valence e-
Cl
Cl C Cl
Cl
Cl
Cl—C—Cl
Cl
Steps for Lewis Dot Structures
1. Determine number of valence
electrons for each element
2. Determine central atom (atom with
lowest electronegativity value)
3. Write central atom and valence
electron dots
4. Fill in remaining elements with their
valence electron dots