1 chemistry 111 chapter 6 - nomenclature. 2 nomenclature – main tasks learn specific rule sets...
TRANSCRIPT
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Chemistry 111
Chapter 6 - Nomenclature
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Nomenclature – Main Tasks
• Learn Specific Rule Sets– Ionic Compounds– Covalent Compounds– Transition Metal Cations
• Learn Oxyanions & Oxyacids– Memorize…
• Practice– Flash Cards! Keep them in your pocket –
pull them out when waiting in lines, during commercials.
• Collate all of this information…
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Nomenclature• Rules / System of Rules (+ exceptions)• Elements• Covalent Compounds• Monatomic Ions
– Regular– Super Sized (super ugly?)
• Polyatomic Anions– 5 “normal”– more & less
• Acids• Formulas of Ionic Compounds• Naming Ionic Compounds• Common Polyatomic Ions (other)
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Naming Elements
• Very Simple – just their names.
• Diatomic Elements– Remember H, O, N, Cl, Br, I, F all come
as diatomic molecules in elemental form
– “HONClBrIF” hon-cul-brif
– H2, O2, …
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Covalent Compounds
• 2 non-metals have covalent bonds.• Naming system needs to indicate how
many of each: CO vs CO2
• Rules:– Use mono-, di-, tri- prefixes (1, 2, 3, …)– End with “-ide”
• Exception:– Skip mono- prefix with 1st element– monocarbon dioxide?
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Monatomic Ions• We learned to figure out the charge of
an ion formed by each element – except transition metals
• How do we name them?– Cations:
• just add “ion”• Ca2+ = “calcium ion” Al3+ = “aluminum
ion”
– Anions• Add “-ide” and “ion”• S2- = “sulfide ion” Cl- = “chloride ion”
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Transition Metal Ions
• Many transition metals have multiple charges (all positive)
• We have to memorize which are which!
• (Naming them will be worse…)
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Common/Important Transition Metal Ions
3B 4B 5B 6B 7B 8B 1B 2B 3A 4A
Sc
Ti V Cr Mn
Fe
Co
Ni Cu
Zn
Ga
Ge
Y Zr
Nb
Mo
Tc Ru
Th
Pd
Ag
Cd In Sn
La
Hf
Ta W Re Os
Ir Pt Au Hg
Tl Pb
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Common/Important Transition Metal Ions
6B 7B 8B 1B 2B 3A 4A
Cr2+
Cr3+
Fe2+
Fe3+
Cu+
Cu2+
Zn2+
Ag+ Sn2+
Sn4+
Hg22
+
Hg2+
Pb2+
Pb4+
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Naming Transition Metal Ions with Multiple Charges• Stock System
– Use a roman numeral with the charge.
– Use English Name
• Fe3+ = iron (III) ion• Fe2+ = iron (II) ion• Sn4+ = tin (IV) ion• Zn2+ = zinc ion
• Old System– Use endings to
indicate charge– Higher “-ic”– Lower “-ous”– Use latin names
• Fe3+ = ferric ion• Fe2+ = ferrous ion• Sn4+ = stannic ion
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Naming Mercury
• Hg22+ has +2 spread over 2 mercury
atoms– mercury (I) ion, mercurous ion
• Hg2+ has +2 on 1 mercury atom– mercury (II) ion, mercuric ion
• Note that it’s a double exception – we don’t use the latin name!
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More Nomenclature
• Polyatomic Anions– 5 “normal”– more & less
• Acids• Formulas of Ionic Compounds• Naming Ionic Compounds• Common Polyatomic Ions (other)
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Polyatomic Anions• These are molecules with negative
charge.• Inside the anion, bonding is covalent.• Outside they form ionic bonds.• Be sure to treat the poly-ions as a whole
unit!
shared electrons lost 1 electonO Cl O[ ]- Na+
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How do we learn all of these?
• (Table 6.8)
1. Memorize the whole table.2. Learn a system…
(more of Herbelin’s propaganda)
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Oxyanion System
1. Learn (memorize) the 5 “normal” anions.
• Element• Charge• # of oxygens• “-ate”
2. Learn how to add/subtract oxygens.
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5 “Normal” Oxyanions
Element
# Oxygen
Charge
Formula
Name
N 3 -1 NO3- nitrate
Cl 3 -1 ClO3- chlorate
C 3 -2 CO32- carbonat
e
S 4 -2 SO42- sulfate
P 4 -3 PO43- phosate
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Changing the Number of Oxygens
• The ending shows how many oxygens are on an oxyanion:
-ate = normal number-ite = 1 fewer oxygens
• Nitrate NO3-, Nitrite NO2
-
• Anion keeps the same charge!
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What about other elements?
• What is SeO42- ?
– “selenate”• How do you know it’s “ate”?
– Selenium is just below Sulfur. – Use the periodic trend.
• Atoms below the five normal elements follow the ones above them.
• Exception: What’s below N?
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Special Halogen Oxyanions
• Halogens form 2 extra anions:– per-chlor-ate ClO4
- per = 1 more
– chlor-ate ClO3- “normal”
– chlor-ite ClO2- -ite = 1 less
– hypo-chlor-ite ClO1- hypo-ite = 2 less
(ClO-)
• Note: – charge stays the same.– No oxygens (Cl-) = chloride (easy rules)
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Naming Acids• Acids are poly anions with enough H+ to balance
the charge:
Anion Name Acid Name
CO32- carbonate H2CO3 carbonic acid
ClO3- chlorate HClO3 chloric acid
ClO2- chlorite HClO2 chlorous acid
ClO- hypochlorite HClO hypochlorous
acid
PO3- phosphite H3PO3 phosphorous
acid
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Naming Acids
• per-ate per-ic• -ate -ic• -ite -ous• hypo-ite -hypo-ous
• NoneHCl hydrochloric acid
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Half-Way Hydrogens
• You can put only some hydrogen (H+) on your polyatomic ions:– HSO4
- hydrogen sulfate– HCO3
- hydrogen carbonate(bicarbonate)
– HPO42- monohydrogen
phosphate– H2PO4
- dihydrogen phosphate
• Read your twinkies!
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Naming Ionic Compounds
cation + Space + anion
• Drop the word Ion• Anion will end with either:
–ide or–ate/-ite
• Note: we don’t use any number information on these.
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Examples
• Na+ Cl- Sodium chloride, NaCl
• Na+ NO3- Sodium nitrate,
NaNO3
• K+ SO42- potassium sulfate,
K2SO4
• Al3+ NO3- aluminum nitrate,
Al(NO3)3
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Charge Balance
• Ionic compounds have to be Neutral• Charge Balance gets them to the
same number.• The math is “least common multiple”
• We can also “cross” & simplify.Al3+ NO3
-1
Al1(NO3)3 Al(NO3)3
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Other Polyatomic Ions
• Cations:– NH4
+ ammonium ion
– H3O+ hydronium ion
• Anions:– CH3COO- or C2H3O2
- acetate ion
– CN- cyanide ion– SCN- thiosyanate ion (thio = sulfur = smelly)
– O22- peroxide ion (weird: oxygen = -1, not
–2)