BONDING REVIEW
You must know this:
1.
2.
3.
4.
5.
6.
Ionic bonds happen with a metal and a nonmetal transferring electrons.
Ionic bonds are never single, double or triple.
Because of the positive and negative ions, ionic bonds are inherently polar
Ionic bonds are the strongest of bonds, holding together by opposite charge.
Ionic bonds form ionic compounds.
Aqueous ionic compounds contain loose ions in water, and these solutions will
conduct electricity.
7. Solutions that conduct electricity are electrolytes
8. Ionic compounds that cannot dissolve (ionize) in water are not electrolytes.
9. Ionic compounds that COULD ionize in water, but are solids are still
electrolytes by definition, but cannot conduct electricity as solids
10. All ionic compounds that are melted contain loose ions and can conduct
electricity
11. If you’re a compound and your first name is a metal, you are ionic
And this:
11. 2 or more non metals that share valence electrons are making covalent bonds.
12. Most atoms follow the octet rule when sharing electrons
(they fill outer orbital to 8e─)
13. Skip this one, okay.
14. Electrons are shared evenly or not, depending upon the electronegativity
differences between the atoms
15. An EN Difference of zero means the bond is nonpolar
16. A difference in EN Value means the bonds are polar
17. The greater the difference, the greater the bond polarity
18. Bonds can be polar due to this EN Difference,
19. Molecules can be polar due to their shape: Radial symmetry = nonpolar
20.Radial symmetry means cut through the center and get 2 equal sides
21. Molecules with radial symmetry are “balanced” and the polarity of the bonds
is offset, or balanced.
22.Polar molecules are “sticky” and will have greater melting points, greater
boiling points, and lower vapor pressure (won’t evaporate as well)
23.You can rank molecules, predict their physical properties (MP, BP, VP) by their
shapes/their molecular polarities
Metallic bonding
24.Metals are thought to be packed cations with loose valence electrons
25.This arrangement explains malleability, ductility, and electrical conduction
26.Metals melted together with other metals, or even nonmetals, form into alloys
Intermolecular bonding
30.There are three kinds of intermolecular bonding in HS Chem
31. The weakest is called ELECTRON DISPERSION, due to the constant
movement of the electrons. All atoms and all compounds have this.
32.We usually look to group 17 to help explain this idea
33.Electrons move very fast but at an moment they are not spread out exactly
evenly in the orbital
34.This temporary, instantaneous dispersion of electrons causes spots of positive
and negative to exist in the valence orbital of any atom or compounds
35.These temporary polar spots are attracted to each other (when opposite) and
this causes some weak but measurable intermolecular attraction.
36.The more electrons you have, the stronger these temporary moments of
polarity can be: F2 and Cl2 have the fewest electrons, they are gases at STP
because they have the weakest temporary moments of orbital polarity
37.Br2 has more electrons, and they move more and create stronger moments of
polarity in the orbitals. Bromine is a liquid at STP because of this weak but
ever strengthening attraction due to the movement of electrons.
38.I2 has the most electrons in group 17 and has the strongest intermolecular
attraction called electron dispersion force, and is a SOLID at STP.
39.The second intermolecular attraction is called DIPOLE ATTRACTION. This is
caused by the semi-permanent molecular polarity of polar bonds in polar
molecules.
40.SCl2 has polar bonds and does not have radial symmetry, so it’s a polar
molecule. It has a positive side most of the time (sulfur) and a negative side
most of the time (chlorine). Sulfur from one molecule is most often attracted
to chlorine of another molecule. This “magnetic” attraction is near constant.
It’s weak, but stronger than electron dispersion.
41. The more polar the bonds in the polar molecules, the stronger this dipole
attraction is.
37.The third intermolecular attraction is called HYDROGEN BONDING. This
is really just SUPER DUPER dipole attraction, which exists when hydrogen
atoms are involved in the polar bonds.
38.Because relatively speaking, the H atoms have such low electronegativity
values, the polarity that can develop with H-F is so much greater when
compared to the polarity between SCl2, they give this “SUPER-DUPER
DIPOLE” a new name: hydrogen bonding.
Odd Ball Bonding
44.Resonating bonds exist in ozone, or O3. A double bond/single bond situation
resonates back and forth because neither of these two bonds is stable as is.
This double/single reverses to single/double, and back over and over
45.Coordinate covalent bonds exist when an atom “helps” another atom obtain
an octet in an odd way. CO, carbon monoxide has a “normal” double polar
covalent bond. This gives the oxygen an octet but not the carbon atom. In
order to get an octet, the oxygen atom pushes two of it’s unshared pairs of
electrons “into the middle” so that the carbon can borrow them as well.
44.PCl5 bonds in “normal” polar covalent bonds, but the phosphorous can “get”
10 valence electrons somehow. This breaks the octet rule, but it happens.
45.When ionic compounds dissolve into water, loose positive and loose negative
ions float in the water. The water can only hold a certain amount of ions
(saturation).
46.The water molecules will “orient” to the ions. For example, positive sodium
cations are surrounded by water molecules, but only with the negative sides
of the oxygen atoms of the water molecules.
47.The negative chloride ions in water will also be surrounded by water
molecules, but only by the positive hydrogen sides of the water molecules.
You should instantly be able to decide if a compound is ionic or covalent
You should know the difference between bond polarity and molecular polarity
You should be able to determine which molecule has a lower vapor pressure (or
higher BP) by it’s polarity, example: methane CH4 and water H2O
You should be able to rank bond polarity by electronegativity differences
You should be able to rank intermolecular bond strength, giving examples of each
You should be able to name bonds like: ionic, single/double/or triple, polar or
nonpolar covalent bonds
You should know your vocabulary
You should be able to draw ionic and covalent compounds as Lewis Dot diagrams.
You should be able to draw covalent compounds as structural diagrams
You should know when a single dash, double dash, and triple dash are necessary
You should be able to explain the oddball bonding in ozone, carbon monoxide,
phosphorous pentachloride
You should be able to define and explain with examples allotropes
You should be able to answer all 100 questions on the blue sheets that I handed
out, and they are online (homepage, right side click bonding, click 100 questions
about bonding)
Etc.