Lewis Dot Structures
Intermolecular Forces
Ionic & Covalent Bonds
Molecular Geometry
Heating & Cooling Curves
100
Draw the Lewis dot structure for NH3.
100
What 3 elements can form hydrogen bonds?
oxygen
fluorine
nitrogen
100
What is the difference between an ionic bond and a covalent bond.
ionic = metal + nonmetal
covalent = nonmetal + nonmetal
100
What is the molecular geometry of a molecule of Br2?
linear
100
Condensation is the phase change from _____________ to ____________.
+200 points if you can provide an example!
gas; solid
morning dew, breathing on glass, steam on a pot cover/mirror, a cold glass of water
200
What is wrong with Lewis dot structure "B"?
Each hydrogen has too many bonds.
200
Explain, in terms of intermolecular forces, why water has a lower boiling point than sodium.
Water has weaker intermolecular forces than sodium.
Sodium has stronger intermolecular forces than water.
200
Draw all dipoles in a molecule of H2O.
200
What is the molecular geometry of BF3. Draw the Lewis dot structure to help you!
trigonal planar
Boron is one of the exceptions! Only 6 valence electrons!
200
On a cooling curve, what phase of matter does the curve start with? How is this different from a heating curve?
cooling curve = start with gas
heating curve = start with solid
300
Methanol is an alcohol that can be used to produce acetic acid found in vinegar. Draw the Lewis dot structure for methanol (CH3OH).
300
Compare the intermolecular forces of the substance at Point "3" and Point "5." 
The intermolecular forces at Point "3" are stronger than at Point "5."
The intermolecular forces at Point "5" are weaker than at Point "3."
300
Magnesium (Mg) will readily react with bromine (Br) to for magnesium bromide (?). Magnesium bromide is commonly used to treat epilepsy and bipolar disorder. Draw the Lewis dot structure for magnesium bromide.
300
Why do we say that the polarity of a tetrahedral molecule "depends"?
The polarity depends on what surrounds the central atom.
If all of the surroundings atoms are the same, the dipoles cancel, and the molecule is nonpolar (symmetrical).
If the surrounding atoms are different, the dipoles do NOT cancel, and the molecule is polar (asymmetrical).
300
On a heating curve, how do you determine the melting point?
400
What is wrong with Lewis dot structure "F"?
Carbon does not have 4 bonds.
Carbon has 1 lone pair.
Oxygen does not have 2 bonds.
400
Image that you have a beaker of HBr. What intermolecular forces holds all of the molecules together?
dipole-dipole force
400
BONUS (400 x 2 = 800 points)
Are diatomic particles ionic or covalent compounds? How do you know?
Covalent. They are all nonmetals.
H N O F Cl Br I
400
What molecular geometry is demonstrated in the following image? Is this molecule polar or nonpolar? 
trigonal pyramidal (3 groups, 1 lone pair)
polar
400
What is happening to water's kinetic energy at 12 minutes? What phase is water at 12 minutes?
Water is a liquid at 12 minutes. It is cooling down. It's kinetic energy is decreasing.
500
Draw the lewis dot structure for hydroxylamine (NH2OH).
500
State an intermolecular force that exists between HI molecules, but does not exist between CO2 molecules.
dipole-dipole
500
How many calcium atoms need to combine with 4 bromine atoms to produce a stable compound?
2 calcium atoms (4+)
4 bromine atoms (4-)
500
Observe the following molecule. Based on the molecular geometry, is this molecule polar or nonpolar? How would you change the polarity?
nonpolar
change one of the oxygens to something else; that will change the symmetry, making the molecule polar
500
Which substance is a solid at room temperature (25oC)?
phenol