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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

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• 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)