Bonding:
1. Atoms gain, lose or share electrons to form bonds.
2. When bonds FORM, energy is RELEASED
3. When bonds BREAK, energy has been absorbed
4. There are 3 TYPES of bonds: Ionic, Covalent, and Metallic
5. Ionic Bonding:
a) Involves a transfer of electrons
b) from the “metal to the nonmetal”
c) forming CATIONS ( + ions) and ANIONS (- ions)
d) takes place essentially between
a Metal/ Nonmetal Ex. NaCl
a Metal/ Pai
Ex. K2SO4
a Pai/ Pai
Ex. (NH4)2CO3
a Pai/Nonmetal
Ex. NH4Cl
6. Compds with Pai’s have BOTH ionic and covalent bonds
Ex. NaOH (ionic holds the Na+ to the OH-, BUT covalent
holds the O to the H)
7. Metallic Bonding:
a) holds all atoms of a metal together
b) “sea of mobile valence electrons” surround
positive metal ions
c) accounts for great electric conductivity of
metals
8. Covalent Bonding:
a) involves a SHARING of electrons
between 2 or more of the SAME or DIFFERENT
nonmetals
b) polar covalent bonds: unequal share
mostly between 2 DIFF nonmetals Ex. HCl
c) nonpolar covalent: equal share
between 2 of SAME nonmetals Ex. H-H
9. VSEPR theory=electrons repulse each other. This
affects bond angles and shape.
Shape etc, helps predict properties.
10. Shapes Chart:
Lone Shared Shape Angle Ex
pairs pairs
pyramidal
1
3
Trigonal
planar
tetrahedral
bent
linear
11. Dipole: molecule with 2 Di-fferent ends; a dipole has
BOTH polar bonds AND asymmetry
12. POLARITY of the WHOLE MOLECULE:
Polar Molecules are ASYMMETRICAL
( uneven charge distribution)
Ex. H----F, NH3
Nonpolar Molecules are SYMMETRICAL
(even charge distribution)
Ex. H---H, CH4
13. POLAR MOLECULES must have polar
bonds BUT NONPOLAR molecules COULD
have either nonpolar OR polar BONDS
Bond
Type
Polar
Covalent
Nonpolar
Covalent
Molecular Polarity
Polar
molecule
(dipole)
NonPolar
Molecule


Ex. H-F
X
Ex. CCl4


Ex. H-H
14. Bonds are between atoms WHILE Forces of attraction
(IMF’s) are BETWEEN molecules. Ex. Dipole-dipole,
and Hydrogen “Bonding”, and London Dispersion
15. Dipole-Dipole IMF attraction: a weak force of attraction
between 2 dipole molecules, in which the slightly + end of
one, is attracted to the slightly (-) end of the other. Ex.
between HCl and HCl
16. Hydrogen "bonding": Strongest IMF due to EXTREME
dipole-dipole IMF; characterized by
H---F, H---O, and H---N bonds [et FON Home];
accounts for the high b.p. of water
17. London dispersion: exists between nonpolar
molecules despite no polar ends to attract each other
until instantaneous (induced) dipole moment forms;
increases as molecule distance decreases and as mass
increases.
18. molecule-ion (dipole-ion) IMF: the 4th INTER-“molecular” force of attraction between ions
(as in a salt like NaCl) and a dipole like a water molecule. This force of attraction is especially
important in the dissolving process of ionic substances in polar solvents to form
solutions.
SOLUTIONS:
1. SOLUTIONS: Solute= material BEING dissolved. Ex. Sugar or coffee grinds into
coffee. Solvent= the material DOING the dissolving. Ex. The hot water for the
coffee
2. Factors that affect DEGREE of Solubility (HOW MUCH can be dissolved)
include: Nature of solute/solvent (Polarity), temp, how much solute already
dissolved, and pressure (gases only)
3. Degree(Polarity): “Like dissolves Like”:
A polar solvent such as water, will
dissolve a polar solute (or an ionic
one) Ex. HCL in H20, OR, Ex. NaCl in H20,
and a nonpolar solvent will dissolve a
nonpolar solute Ex. CO2 gas in O2 gas
4. Degree(Pressure) GASES ONLY: More gas dissolves as
the pressure of the gas over its solvent increases
(Henry’s Law) Ex. CO2 (carbonation) added to soda under high
Pressure; Nitrogen in diver’s bloodstream at great pressure
(bends)
5. Degree(temp): the higher the temp of the solvent the more SOLID/LIQUID solute
dissolves (ex. More sugar dissolves in HOT coffee than in COLD coffee)
**** For Gases: the higher the temp of solvent the (continued next page)
LESS gas dissolves (warm soda=flat soda)
6. Factors that affect RATE of solubility (How FAST a solute dissolves) include
stirring, temp, and surface area
7. Stirring: For SOLID and LIQUID solutes= as stirring increases so does how fast
the solute dissolves. (Stirring sugar makes it dissolve faster)
*** For Gases: stirring decreases degree and increases rate of solubility
8.Temp: increasing the temp of a solvent increases the rate of dissolving
for a solid or liquid solute. (Hot coffee dissolves sugar faster).
*** Increasing the temp of a solvent decreases the rate at which
a gas dissolves (hot soda=flat soda)
9. Surface Area: the greater the surface area of a solid solute, the faster
the solute dissolves