Download Chapter 19 - Google Groups

Chapter 19
Metallic character increases going down a group
Define “metallic character”
Group 5A
Form molecules that or ions that involve 3,5 or 6 covalent bonds to the 5A atom.
MX3 = everyone and pyramidal shape (figure 19.1)
MX5 = everyone but nitrogen (too small) and trigonal bipyramidal shape dsp3 hybridized
MX6 = ionic species formed from MX5 octahedral shape d2sp3 hybridized
Nitrogen
Almost all of it is in the form of N2 super strong bond that is rarely broken therefore
practically inert when it does break it is highly exothermic which is why it is good for
explosives.
Haber process
Nitrogen fixation
Nitrogen Hydrides
Ammonia – hydrogen bonding accounts for high boiling point (why not as high as
water?). Acts as a base
Hydrazine – basically a rocket fuel when mixed with O2 or other halide goes to N2 and
X2O in a self starting and highly exothermic reaction
Nitrogen Oxides
N2O high solubility in fats makes it useful for whipped cream, controls earth’s
temperature like carbon dioxide does
NO very important in biological regulation
Draw a molecular orbital diagram of NO (page 900)
Oxyacids of Nitrogen
Nitric acid industrially important produced by the Ostwald process (is it an oxidizing or
reducing agent?) walk yourself through the Ostwald process and be sure you follow it as
a good exercise
Phosphorus
Very different from Nitrogen (why?) nitrogen’s stronger pi bonds, nitrogen is more
electronegative, phosphorus is larger and phosphorus has empty d orbitals.
Because of the strong pi bonds, N is almost always in N2, but P is usually in aggregates.
( PH3 versus NH3 which is a stronger base? Why? - electronegativity )
Phosphorus oxides and oxyacids
P reacts with O to form oxides than leave P in +5 or +3 excess O results in P4O10 and
limited O results in P4O6. Actually, P will form with all the halides PX3 and PX5
except PI5
Compare phosphoric acid to nitric acid (webpage)
Compare to phosphorus acid (H3PO4) to phosphoric and hypophosphorous acid
(H3PO2)
In nature P is only found in combos unlike N
You may have to determine products from P purifications, take a look at them.
Def be able to determine the oxidation state of central atom and hybridization in all these
compounds!!
Group 6A elements
More metallic as you go down but none of these are very metallic – pretty much
nonmetals except maybe Po.
‘usually react with a metal to get an octet and end up as –2 anions. Which is why you see
so many metals as oxides or sulfides
they can also form covalent bonds with nonmetals like H and end up as H2X
Te and Po can lose electrons to get an octet by becoming a cation (why don’t the others?)
Oxygen
20% is in O2
Paramagnetic – draw the molecular orbital diagram ( 14.41) for O
Ozone draw the resonance structure
(Ozone is an oxidizing or reducing agent? Stronger or weaker than O2? How do you
know? Why does ozone protect against sunburn?)
Sulfur
Free element and in ores.
Frasch process
S2 is not common because the sigma bonds it forms are so much stronger than the pi
bonds it forms. So it ends up in aggregates.
Why doesn’t it form SO? Again with the pi bonds.
SO2 is formed when S is burned in the air and then you can add more O to get S03 but it
is kinetically challenged without a catalyst.
Draw the resonance structures of SO2 and SO3
Oxyacids of sulfur
SO2 in water makes H2SO3 but not much
SO3 in water makes H2SO4
Compare to nitric and P acids
Other compounds with S
Reacts with metals and nonmetals to form compounds in which it has +6,+4,+2,0, or –2
look at table 19.5 and be familiar with those compounds and their hybridization/structure
H2S reducing or oxidizing agent? How is it different from water?
7A elements
Halogens all nonmetals totally nonmetals very important
Highly reactive not found free but with a +1 see table 19.7
Form polar covalent bonds with metals and ionic bonds with metals in lower oxidatin
state
Halides rate depends on electro negativity.
Why does HF have such a high boiling point? Halides are acids strength depends on
Electronegativity look at page 916-918
Oxyacids and oxyanions
Everyone but F form oxyacids strength varies with number of oxygen atoms attac hed to
the halogen (why?)
Interhalogen elements ABn where n =1,3,5 or 7 (which is A and which is B? A is the
larger)
8A elements
noble gases filled s and p orbitals nonreactive (well sort of with lots of tricks) no much to
know
Chapter 20
Transition Metals
Chemistry changes a lot across a period as number of valence electrons changes –
usually. Not true of transition metals they are similar within a period also. Because the
last electrons added are added to inner orbitals which can’t bond.
Typical metals, conductor of heat, and electrons
Know the exceptions to filling
Lose one or more electron table 20.2 why do Sc and Ti lose all valance and Cu and Zi
don’t? nuclear charge
Reduction potentials – listed in opposite order as table of standard reduction potentials so
watch your signs when doing calculations
Look at 4d and 5d lathanide contraction
Coordination compounds
Square bracket convention review section 8.10
Coordination number is just “how many things are attached to the central atom”
Ligands form a coordinate covalent bond with metals, they can be neutral or ionic but
they must have a lone pair to donate to form the bond.
Review naming summary on page 946 and example 20.1 on page 947
Isomers
Same formula = isomers
Same atoms, different connectivity/bonds = structural isomers
Different composition of complex ion = coordination isomer
Same complex ion, different point of attachment of ligands = linkage isomers
Same connectivity / bonds = stereoisomers
Arranged differently = geometeric or cis-trans isomers
Non-superimposable mirror images = optical isomers or enantiomers
Chapter 22
Hydrocarbons = just carbon and hydrogen
Single bonded carbons = saturated (have the most hydrogens they can take)
Double bonded carbons = unsaturated (could take extra carbon if you broke some bonds)
Alkanes – a means single bonds
Alkenes – e means double bonds
Alkynes – y means triple bonds
Meth, eth, prop, but, pent, hex , hept, oct , non, dec
When you use a y that means it is a substituent of something else
Many structural isomers
1.
2.
3.
4.
5.
use the prefix and ane for the longest string of carbons
the shorter string(s) or carbons use the same prefixes but a yl ending
number the carbons starting closest to the branch point
name = carbon number where branch is -____yl____ane
may have to put di, tri etc in front of ____yl
Alkanes undergo subsitution and dehydrogenation reactions
Also form rings, naming is pretty much the same with the addition of cyclo
Alkenes and Alkynes
Naming is the same with a vowel change
Undergo substitution reactions