1 Chemistry 111 Chapter 6 - Nomenclature. 2 Nomenclature – Main Tasks Learn Specific Rule Sets...

1

Chemistry 111

Chapter 6 - Nomenclature

2

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…

3

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)

4

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, …

5

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?

6

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”

7

Transition Metal Ions

• Many transition metals have multiple charges (all positive)

• We have to memorize which are which!

• (Naming them will be worse…)

8

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

9

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+

10

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

11

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!

12

More Nomenclature

• Polyatomic Anions– 5 “normal”– more & less

• Acids• Formulas of Ionic Compounds• Naming Ionic Compounds• Common Polyatomic Ions (other)

13

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+

14

How do we learn all of these?

• (Table 6.8)

1. Memorize the whole table.2. Learn a system…

(more of Herbelin’s propaganda)

15

Oxyanion System

1. Learn (memorize) the 5 “normal” anions.

• Element• Charge• # of oxygens• “-ate”

2. Learn how to add/subtract oxygens.

16

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

17

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!

18

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?

19

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)

20

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

21

Naming Acids

• per-ate per-ic• -ate -ic• -ite -ous• hypo-ite -hypo-ous

• NoneHCl hydrochloric acid

22

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!

23

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.

24

Examples

• Na+ Cl- Sodium chloride, NaCl

• Na+ NO3- Sodium nitrate,

NaNO3

• K+ SO42- potassium sulfate,

K2SO4

• Al3+ NO3- aluminum nitrate,

Al(NO3)3

25

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

26

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)