chemical nomenclature mixtures versus compounds law of definite proportions chemical bonds, ionic...
TRANSCRIPT
Mixtures• Mixtures are physical (NOT chemical) combinations
– Many mixtures have NO chemical reaction potential• Sugar or Salt dissolved in water• Solder, a mixture of Tin and Lead• Unlimited number of potential combinations
– Some mixtures have chemical reaction potential• Rocket Propellants (e.g. zinc + sulfur)
– Mixture of oxidizer and combustible material• Gunpowder (Charcoal + Sulfur + Potassium Nitrate)
– Stable for hundreds of years until ignited• Thermite (iron oxide + aluminum powder)
– Reacts yielding liquid iron to weld railroad track • Hydrogen and Oxygen, gasoline and air
– Requires an initiator (e.g. heat from spark or flame)– Other mixtures are inherently unstable
• Metallic Sodium and water react violently• Liquid rocket propellants burn when mixed• Acids and Bases neutralize each other
Thermite Reaction Al + Fe2O3 Al 2O3 + Fe
An “unstable” mixture reacts to create new compounds
Compounds• Inorganic compounds, “entangled elements”
– Chemical reaction creates bonding + heat energy• Constituents are no longer mechanically separable• Creation of a new material unlike the constituents
– Gaseous hydrogen and oxygen burn to form liquid water
– Metallic sodium and chlorine gas combine to form table salt
– Aluminum and “rust” create liquid iron + lots of heat
• Law of Definite Proportions– Atoms usually combine in small integer multiples– Inorganic common ratios are 1 to 5
• NaCl, CaCl2, Al2O3 , H2SO4, PCl5
Molecules, Ions, Chemical Bonds• Ionic Bonds
– Complete charge separation• Electrons relocated from donor to acceptor atoms • Unlike atoms involved (e.g. Sodium Chloride)
– Opposite sides of periodic table
• Dissolve in water to form charged ions
– Ionic crystals formed when no solvent• Electrostatic “binding energy” holds crystal together
– No distinct partnering• All Na and Cl ions are equivalent in solution or solid crystal• Neutral charge balance, but joined pairs of ions
Los Alamos National Laboratory's Periodic Table
Group**
Period 1 IA 1A
18
VIIIA 8A
1 1 H
1.008
2
IIA 2A
13
IIIA 3A
14
IVA 4A
15
VA 5A
16
VIA 6A
17
VIIA 7A
2 He 4.003
2 3
Li 6.941
4 Be 9.012
5 B
10.81
6 C
12.01
7 N
14.01
8 O
16.00
9 F
19.00
10 Ne 20.18
8 9 10
3 11
Na 22.99
12 Mg 24.31
3
IIIB 3B
4
IVB 4B
5
VB 5B
6
VIB 6B
7
VIIB 7B
------- VIII -------
------- 8 -------
11
IB 1B
12
IIB 2B
13 Al 26.98
14 Si
28.09
15 P
30.97
16 S
32.07
17 Cl
35.45
18 Ar 39.95
4 19 K
39.10
20 Ca 40.08
21 Sc 44.96
22 Ti
47.88
23 V
50.94
24 Cr 52.00
25 Mn 54.94
26 Fe 55.85
27 Co 58.47
28 Ni 58.69
29 Cu 63.55
30 Zn 65.39
31 Ga 69.72
32 Ge 72.59
33 As 74.92
34 Se 78.96
35 Br 79.90
36 Kr 83.80
5 37
Rb 85.47
38 Sr
87.62
39 Y
88.91
40 Zr
91.22
41 Nb 92.91
42 Mo 95.94
43 Tc (98)
44 Ru 101.1
45 Rh 102.9
46 Pd 106.4
47 Ag 107.9
48 Cd 112.4
49 In
114.8
50 Sn 118.7
51 Sb 121.8
52 Te 127.6
53 I
126.9
54 Xe 131.3
6 55
Cs 132.9
56 Ba 137.3
57 La* 138.9
72 Hf 178.5
73 Ta 180.9
74 W
183.9
75 Re 186.2
76 Os 190.2
77 Ir
190.2
78 Pt
195.1
79 Au 197.0
80 Hg 200.5
81 Tl
204.4
82 Pb 207.2
83 Bi
209.0
84 Po (210)
85 At (210)
86 Rn (222)
7 87 Fr
(223)
88 Ra (226)
89 Ac~ (227)
104 Rf (257)
105 Db (260)
106 Sg (263)
107 Bh (262)
108 Hs (265)
109 Mt (266)
110 ---
()
111 ---
()
112 ---
()
114 ---
()
116 ---
()
118 ---
()
Lanthanide Series*
58 Ce 140.1
59 Pr
140.9
60 Nd 144.2
61 Pm (147)
62 Sm 150.4
63 Eu 152.0
64 Gd 157.3
65 Tb 158.9
66 Dy 162.5
67 Ho 164.9
68 Er
167.3
69 Tm 168.9
70 Yb 173.0
71 Lu 175.0
Ionic CrystalsHeld together by electrostatic attraction• Opposite charge attraction • A 3-D array of ions
Molecules, Ions, Chemical Bonds
• Ionic Bonds– “Cation” is positively charged ion
• Attracted to “Cathode” which is negative pole• Typically a metal with 1-3 missing electrons
– Na1+, Ca2+, Fe3+
– “Anion” is negatively charged ion• Attracted to “Anode” which is a positive pole• Typically a halogen or oxide with 1-2 extra electrons
– F1-, Br1-, O2- …
• Polyatomic Anions also very common– These are very stable molecular species
– NO31-, SO4
2-, PO43-
NaCl dissolving in waterEach ion “solvated” by water molecules, attracted to
oppositely charged ends of water moleculesEqual numbers of Na+ & Cl- ions in solution
Molecules, Ions, Chemical Bonds
• Covalent Bond– Shared electrons between atoms
• Pair of electrons involved, one from each atom
– Same kind of atoms often linked to each other • Carbon-carbon electron sharing very common
• Diatomic elements: O2, H2, N2, F2 … not He, Ne, Xe
– “Octet Rule” describes stable configurations• Total of 8 electrons around atom most stable
– Exception is Hydrogen = 2 for complete “s” shell
• Can achieve an octet via sharing – My one + your one = two to share
– Carbon is ideal candidate for sharing
» 4 electrons to share with 4 other elements
Covalent bondingInvolves SHARED electrons
• Oxygen forms O2
• Atoms 68 electrons
• Methane, CH4
• Carbon shares 8, hydrogen 2
Los Alamos National Laboratory's Periodic Table
Group**
Period 1 IA 1A
18
VIIIA 8A
1 1 H
1.008
2
IIA 2A
13
IIIA 3A
14
IVA 4A
15
VA 5A
16
VIA 6A
17
VIIA 7A
2 He 4.003
2 3
Li 6.941
4 Be 9.012
5 B
10.81
6 C
12.01
7 N
14.01
8 O
16.00
9 F
19.00
10 Ne 20.18
8 9 10
3 11
Na 22.99
12 Mg 24.31
3
IIIB 3B
4
IVB 4B
5
VB 5B
6
VIB 6B
7
VIIB 7B
------- VIII -------
------- 8 -------
11
IB 1B
12
IIB 2B
13 Al 26.98
14 Si
28.09
15 P
30.97
16 S
32.07
17 Cl
35.45
18 Ar 39.95
4 19 K
39.10
20 Ca 40.08
21 Sc 44.96
22 Ti
47.88
23 V
50.94
24 Cr 52.00
25 Mn 54.94
26 Fe 55.85
27 Co 58.47
28 Ni 58.69
29 Cu 63.55
30 Zn 65.39
31 Ga 69.72
32 Ge 72.59
33 As 74.92
34 Se 78.96
35 Br 79.90
36 Kr 83.80
5 37
Rb 85.47
38 Sr
87.62
39 Y
88.91
40 Zr
91.22
41 Nb 92.91
42 Mo 95.94
43 Tc (98)
44 Ru 101.1
45 Rh 102.9
46 Pd 106.4
47 Ag 107.9
48 Cd 112.4
49 In
114.8
50 Sn 118.7
51 Sb 121.8
52 Te 127.6
53 I
126.9
54 Xe 131.3
6 55
Cs 132.9
56 Ba 137.3
57 La* 138.9
72 Hf 178.5
73 Ta 180.9
74 W
183.9
75 Re 186.2
76 Os 190.2
77 Ir
190.2
78 Pt
195.1
79 Au 197.0
80 Hg 200.5
81 Tl
204.4
82 Pb 207.2
83 Bi
209.0
84 Po (210)
85 At (210)
86 Rn (222)
7 87 Fr
(223)
88 Ra (226)
89 Ac~ (227)
104 Rf (257)
105 Db (260)
106 Sg (263)
107 Bh (262)
108 Hs (265)
109 Mt (266)
110 ---
()
111 ---
()
112 ---
()
114 ---
()
116 ---
()
118 ---
()
Lanthanide Series*
58 Ce 140.1
59 Pr
140.9
60 Nd 144.2
61 Pm (147)
62 Sm 150.4
63 Eu 152.0
64 Gd 157.3
65 Tb 158.9
66 Dy 162.5
67 Ho 164.9
68 Er
167.3
69 Tm 168.9
70 Yb 173.0
71 Lu 175.0
Molecules, Ions, Chemical Bonds
• Why not diatomic He, Ne, Ar, Kr … ?– These already have a full octet
• No need to share for 8 outer shell electrons
– Full outer shell means INERT• No chemical reactions if no electrons to transfer
– NO compounds form with He, Ne, etc.
• Can ionize (remove electrons) with high voltage– Electrons fall back with emission of light– Low pressure Neon (pink) used in signs– Argon (blue) used in high power lasers– Xenon (white) for camera’s electronic flash
Why is the electron negative ?
• Benjamin Franklin responsible !– Published kite in a storm experiment in 1780
• Nobody really knew what electricity was• A dangerous experiment, people killed repeating it
– He applied terms “positive” and “negative”• “Electrical Fluid” was term used at the time • (+) and (-) Used for batteries, electrolysis
• Unfortunately “positive” is backwards– Assumption of flow (+) to (-) was wrong– … but we kept the polarity definitions– Electrons go the other way, are therefore (-)
– See wikipedia on Benjamin Franklin
Element Ionic charges• Alkali metals (1st column) have single (+) charge
– Na+, K+ , Li+
– Usually do NOT write the number for single charge• Alkalai Earth metals (2nd col.) have charge (+2)
– Ca 2+ , Mg 2+
• Transition metals often have multiple valences– Iron can lose 2 or 3 electrons, Fe2+ or Fe3+
– Similar situation with Mn, Cr, Sn, etc.• Old Latin names indicated degree of valence
– “-ic” at end was/is highest valence state (mostly)• But not always the same valence numerical value• Ferric is +3, Stannic is +4
– “-ous” at end was/is lowest valence state (mostly)• Not always the same numerical value
Los Alamos National Laboratory's Periodic Table
Group**
Period 1 IA 1A
18
VIIIA 8A
1 1 H
1.008
2
IIA 2A
13
IIIA 3A
14
IVA 4A
15
VA 5A
16
VIA 6A
17
VIIA 7A
2 He 4.003
2 3
Li 6.941
4 Be 9.012
5 B
10.81
6 C
12.01
7 N
14.01
8 O
16.00
9 F
19.00
10 Ne 20.18
8 9 10
3 11
Na 22.99
12 Mg 24.31
3
IIIB 3B
4
IVB 4B
5
VB 5B
6
VIB 6B
7
VIIB 7B
------- VIII -------
------- 8 -------
11
IB 1B
12
IIB 2B
13 Al 26.98
14 Si
28.09
15 P
30.97
16 S
32.07
17 Cl
35.45
18 Ar 39.95
4 19 K
39.10
20 Ca 40.08
21 Sc 44.96
22 Ti
47.88
23 V
50.94
24 Cr 52.00
25 Mn 54.94
26 Fe 55.85
27 Co 58.47
28 Ni 58.69
29 Cu 63.55
30 Zn 65.39
31 Ga 69.72
32 Ge 72.59
33 As 74.92
34 Se 78.96
35 Br 79.90
36 Kr 83.80
5 37
Rb 85.47
38 Sr
87.62
39 Y
88.91
40 Zr
91.22
41 Nb 92.91
42 Mo 95.94
43 Tc (98)
44 Ru 101.1
45 Rh 102.9
46 Pd 106.4
47 Ag 107.9
48 Cd 112.4
49 In
114.8
50 Sn 118.7
51 Sb 121.8
52 Te 127.6
53 I
126.9
54 Xe 131.3
6 55
Cs 132.9
56 Ba 137.3
57 La* 138.9
72 Hf 178.5
73 Ta 180.9
74 W
183.9
75 Re 186.2
76 Os 190.2
77 Ir
190.2
78 Pt
195.1
79 Au 197.0
80 Hg 200.5
81 Tl
204.4
82 Pb 207.2
83 Bi
209.0
84 Po (210)
85 At (210)
86 Rn (222)
7 87 Fr
(223)
88 Ra (226)
89 Ac~ (227)
104 Rf (257)
105 Db (260)
106 Sg (263)
107 Bh (262)
108 Hs (265)
109 Mt (266)
110 ---
()
111 ---
()
112 ---
()
114 ---
()
116 ---
()
118 ---
()
Lanthanide Series*
58 Ce 140.1
59 Pr
140.9
60 Nd 144.2
61 Pm (147)
62 Sm 150.4
63 Eu 152.0
64 Gd 157.3
65 Tb 158.9
66 Dy 162.5
67 Ho 164.9
68 Er
167.3
69 Tm 168.9
70 Yb 173.0
71 Lu 175.0
Formation of Compounds• Binary Compounds
– Cation + Anion neutral molecule– Simple ratios = “law of multiple proportions”– Atom quantities must yield charge balance
• 2 * Fe3+ + 3 * O2- Fe2O3
• H2SO4 2H+ + SO4
2-
– Molecules must be “real” materials• Use multiplier to clear fractions (e.g. ½ O2)
Naming Compounds
• Binary Inorganic compounds– Compound name starts with an element name
• Same names & symbols on periodic chart• Sodium (Na), Iron (Fe), Cadmium (Cd)
– Cation element (+), then Anion (-) name• Chlorine, oxygen, sulfur
– Anion (-) in binary compound ends in –ide• Sodium Chloride • Iron Oxide, • Cadmium Sulfide
Binary Halogen Acids
• For halogen acids, “hydro” is prefix used– Hydrochloric Acid = HCl
– Avoids confusion with Chloric Acid = HClO3
• Binary Halogen Acids include– Hydrofluoric Acid = Hydrogen Fluoride = HF– Hydrochloric Acid = Hydrogen Chloride = HCl– Hydrobromic Acid = Hydrogen Bromide = HBr– Hydroiodic Acid = Hydrogen Iodide = HI
Formula Writing
• Cation first (usually a metal or hydrogen)– Hydrogen, H (valence +1)– Calcium, Ca (valence +2)– Aluminum, Al (valence +3)
• Anion follows (often a halogen, or gas)– Sulfur Sulfide (valence -2) – Chlorine Chloride (valence -1)– Oxygen Oxide (valence -2)
• Add the two element names, formula is in atomic ratios– Hydrogen Sulfide, H2S ratio follows valence, 2:1– Calcium Chloride, CaCl2 ratio follows valence, 1:2– Aluminum Oxide, Al2O3 ratio follows valence, 2:3
Formula Writing
• Atomic ratios are simple numbers (1, 2, 3 …5)– Find a common denominator number for electrons– Multiply cation valence times anion valence
• Aluminum (+3) * Oxygen (-2) = 6 total electrons involved
– Divide each valence into the common denominator• 6/3 for aluminum = 2, • 6/2 for oxygen =3
– These values are the ratios of the elements• Al2O3
Multi-Atom (poly atomic) molecules
• Many Anion combinations involve Oxygen– Nitrite, NO2
1- Nitrate, NO31-
– Sulfite, SO32- Sulfate, SO4
2-
– Carbonate, CO32- BiCarbonate, HCO3
1-
– Chlorate, ClO31-
– Phosphate, PO43-
…. And a lot more !
Formation of ions NH3 + HCl NH4
+ + Cl-
Polyatomic Oxygen Anions
• Oxygen forms group around other elements– 2, 3, 4 oxygen clusters surrounding another atom
• Stable configuration due to electron sharing– Sharing fills outer electron (valence) shell – “Octet Rule”, 8 is “magic number” for full shells– Shells of 8 creates exceptionally stable configuration
• Anion Groups exist with extra electrons– Gather as many as needed for full shells– “owning” or “sharing” electrons is equivalent
• Sharing is as good as ownership !
• Excess electrons give ion a negative charge
Polyatomic ions, +1 chargeTetrahedral ammonium: N has 5 electrons, H has 1, total = 9
Total deployed is 8, so one “went missing”, charge is +1Hydronium is proton (+1) attached to water, O=6 elect, H=1, total =9
Total deployed is 8, so one “went missing”, ionic charge is +1
Hydronium Ion
Polyatomic Anions, -1 chargeFor NO3
1-, N has 5 electrons, O has 6, total is 18+5=23Total deployed = 24, so 1 extra electron = -1 charge
For NO2-1, N has 5 electrons, O has 6, total is 12+5=17
Total deployed = 18, so 1 extra electron = -1 charge
Nitrate Formation from elements1 additional electron needed to fill all shells of 8,meeting octet rule requires (-1) charge on anion
N
O O
O
N
O O
O
Alternative Nitrate Representations“Ball & Stick” easy to model and understand
“Bubbles” represent electron clouds, sizeWe willuse computer simulations in an experiment
Polyatomic Anions, -2 chargeFor SO4
2-, S has 6 electrons, O has 6, total is 5*6=30Total deployed = 32, so 2 extra electron = -2 charge
For SO32-, S has 6 electrons, O has 6, total is 4*6 =24
Total deployed = 26, so 2 extra electrons = -2 charge
Sulfate Formation from elements2 additional electrons needed to fill all shells of 8,meeting octet rule requires (-2) charge on anion
S
O O
O O
S
O O
O O
Preferred valence often the maximum• Nitrite would rather be Nitrate
– NO2- adds 1 oxygen, becomes NO3
-
• Nitrogen valence goes (+3) (+5)• All valence electrons consumed at (+5)
– Makes it useful as a preservative in sausage• Nitrite consumes oxygen before the meat does
• Sulfite would rather be Sulfate– SO3
2- adds 1 oxygen, becomes SO4 2-
• Sulfur valence goes (+4) (+6)• All valence electrons consumed at (+6)
– Also a preservative, used in wine• Sulfite consumes oxygen before the wine does• Prevents wine into vinegar (until sulfite runs out)
Polyatomic Anions, CarbonateFor CO3
2-, C has 4 electrons, O has 6, total is 4+18=22Total deployed = 24, so 2 extra electron = -2 charge
For HCO31-, C=4, 3O=18, H=1 so total =23
Total deployed = 24, so 1 extra electron = -1 charge
Polyatomic Anions, PhosphateFor PO4
3-, P has 5 electrons, O has 6, total is 5+24=29Total deployed = 32, so 3 extra electron = -3 charge
For HPO42-, P=5 electrons, O=6, H=1, total is 5+24+1 =30
Total deployed = 32, so 2 extra electrons = -2 charge
Formula Writing
• Polyatomic ions behave like other anions– Cl-1, NO3
-1, SO4-2
• Use parenthesis around the polyatomic ion– Subscript beneath parenthesis– Tells how may polyatomic ions involved– Avoids confusion what multiple intended– For Calcium Nitrate:
• Ca(NO3)2 is correct
• … not CaNO32
• … not Ca2NO3
Multiple Valence Cations
• Some elements have multiple valences– Lose up to all electrons in outer shell
• Old Latin names indicate valence– Fe++, Fe(II), or Ferrous versus Fe+++, Fe(III), or Ferric– Sn++, Sn(II), or Stannous versus Sn++++, Sn(IV) or Stannic– Mn++, Mn(II), or Managnous vs Mn++++, Mn(IV), or Manganic– Cr++, Cr(II), or Chromous versus Cr+++, Cr(III), or Chromic
• Latin Names not precise– No valence numbers, only words– Numeric values inconsistent
Electronic Configurationssome elements can either lose or gain electrons
Oxides of Chlorine• Chlorine an unusual case, (+) or (-) valence
– As halogen it exhibits (-1) charge• Due to gaining one electron to fill octet • Valence is -1 in HCl, Hydrochloric Acid
• NaCl, CaCl2, AlCl3, etc.
– Another possibility is to lose electrons• Relatively unstable and reactive compounds
– 7electrons in outer shell, 5 more loosely held• Valence is +1 in HClO Hypochlorous acid
• Valence is +3 in HClO2 Chlorous acid
• Valence is +5 in HClO3 Chloric acid
• Valence is +7 in HClO4 Perchloric acid
More on Latin Names• xxx-”ic” acid yields xxx-”ate” anion
– Nitric acid HNO3 yields nitrate ion, NO3-
– Sulfuric acid H2SO4 yields sulfate ion, SO42-
– Chloric acid HClO3 yields Chlorate ion, ClO3-
– Originally the highest valence state observed
• xxx-”ous” acid yields xxx-”ite” anion– Nitrous acid HNO2 yields nitrite ion, NO2
-
– Sulfurous acid H2SO3 yields sulfite ion, SO32-
– Chlorous acid HClO2 yields chlorite ion, ClO2-
– Originally the lowest valence state observed
More on Latin Names
• What to do after finding MORE valence states than handled by ”ous” and ”ic” suffixes?
• Fix is more words to modify existing descriptors– “hypo” and ‘per” adopted to handle the situation
• “Hypo”-xxx means 1 less oxygen (below “ous”)– Chlorous acid is HClO2
– Hypochlorous acid is HClO– Sodium Hypochorite (Chlorox) is NaClO
• “Per”-xxx means 1 more oxygen (beyond “ic”)– Chloric acid is HClO3
– Perchloric acid is HClO4`
What if it’s not in the text?• Look for “family” relationships in columns
– Sulfur and Selenium have similar properties they are both in periodic chart column 6A
• Sulfate is based on sulfur, SO4- -
• Selenium analog is “Selenate” SeO4 - -
• Tellurium analog would be “Tellurate TeO4 - -
– Cesium is similar to Sodium, in column 1A • Sodium Chloride is NaCl,• Rubidium analog would be RbCl • Cesium analog would be CsCl
Los Alamos National Laboratory's Periodic Table
Group**
Period 1 IA 1A
18
VIIIA 8A
1 1 H
1.008
2
IIA 2A
13
IIIA 3A
14
IVA 4A
15
VA 5A
16
VIA 6A
17
VIIA 7A
2 He 4.003
2 3
Li 6.941
4 Be 9.012
5 B
10.81
6 C
12.01
7 N
14.01
8 O
16.00
9 F
19.00
10 Ne 20.18
8 9 10
3 11
Na 22.99
12 Mg 24.31
3
IIIB 3B
4
IVB 4B
5
VB 5B
6
VIB 6B
7
VIIB 7B
------- VIII -------
------- 8 -------
11
IB 1B
12
IIB 2B
13 Al 26.98
14 Si
28.09
15 P
30.97
16 S
32.07
17 Cl
35.45
18 Ar 39.95
4 19 K
39.10
20 Ca 40.08
21 Sc 44.96
22 Ti
47.88
23 V
50.94
24 Cr 52.00
25 Mn 54.94
26 Fe 55.85
27 Co 58.47
28 Ni 58.69
29 Cu 63.55
30 Zn 65.39
31 Ga 69.72
32 Ge 72.59
33 As 74.92
34 Se 78.96
35 Br 79.90
36 Kr 83.80
5 37
Rb 85.47
38 Sr
87.62
39 Y
88.91
40 Zr
91.22
41 Nb 92.91
42 Mo 95.94
43 Tc (98)
44 Ru 101.1
45 Rh 102.9
46 Pd 106.4
47 Ag 107.9
48 Cd 112.4
49 In
114.8
50 Sn 118.7
51 Sb 121.8
52 Te 127.6
53 I
126.9
54 Xe 131.3
6 55
Cs 132.9
56 Ba 137.3
57 La* 138.9
72 Hf 178.5
73 Ta 180.9
74 W
183.9
75 Re 186.2
76 Os 190.2
77 Ir
190.2
78 Pt
195.1
79 Au 197.0
80 Hg 200.5
81 Tl
204.4
82 Pb 207.2
83 Bi
209.0
84 Po (210)
85 At (210)
86 Rn (222)
7 87 Fr
(223)
88 Ra (226)
89 Ac~ (227)
104 Rf (257)
105 Db (260)
106 Sg (263)
107 Bh (262)
108 Hs (265)
109 Mt (266)
110 ---
()
111 ---
()
112 ---
()
114 ---
()
116 ---
()
118 ---
()
Lanthanide Series*
58 Ce 140.1
59 Pr
140.9
60 Nd 144.2
61 Pm (147)
62 Sm 150.4
63 Eu 152.0
64 Gd 157.3
65 Tb 158.9
66 Dy 162.5
67 Ho 164.9
68 Er
167.3
69 Tm 168.9
70 Yb 173.0
71 Lu 175.0
Valence Naming Summary• Latin Names: Ferrous, Ferric, Chromic, ..
– Good = easy to say and type– Bad = inconsistent, no numbers to rely on
• Roman Numerals: Fe(III), Sn(IV)– Good = easy to type– Bad = clumsy to say, antiquated Roman Numbering
• Plus and Minus signs : Fe++, SO4 - -
– Good = intuitive, fast to hand write, clarity– Bad = inconvenient to type, clumsy for large valence values
• Arabic character with sign: Fe2+
– Good = intuitive, clarity, good for large valences– Bad = inconvenient to type
• Bottom Line … you will run into ALL of these– Be prepared !
Nomenclature for 32A• Now to the nomenclature dry lab (no goggles today)
– Important issue, learning the language of chemistry
• We’ll use the lab manual– Introduction– Tables of ions pages– Naming Matrix, supply BOTH formula +name in box– Naming exercises, page– Binary compounds, page– Use Google, Wikipedia, other great web resources– Collaboration is OK, but don’t just copy from others
• You don’t learn much by copying• often a source of wrong answers, • Brain damage, if you learn and remember wrong answers
– Due next week