Nomenclature

Naming and Formula Writing

Nomenclature

A term that describes the system of principles, procedures, rules, or terms related to naming.

We use nomenclature to have a uniform set of rules for naming and writing formulas for chemical compounds.

The IUPAC (International Union of Pure and Applied Chemistry) establishes these rules.

Review of Key Vocabulary

Ionic Compounds – contain bonds between metals and nonmetals A bond involving a TRANSFER of electrons A bond between cations and anions

Cation – An atom that has lost one or more electrons. It has a positive (+) charge.

Anion – An atom that has gained one or more electrons. It has a negative (-) charge.

More Key Vocabulary

Binary Compound – A substance that has only 2 different elements. MgCl2 NaCl H2O

Ternary Compound – A substance that has 3 or more different elements. NaOH H2SO4 CH3Cl

More Key Vocabulary

Prefix – A few letters placed at the beginning of a word to change its meaning.NonmetalCarbon dioxide – CO2

Carbon monoxide – CO

More Key Vocabulary

Ending / Suffix – A few letters placed at the end of a word to change its meaning.LaughablePortableCalcium Sulfate – CaSO4

Calcium Sulfite – CaSO3

Calcium Sulfide – CaSCalcium Oxide - CaO

Ionic Nomenclature

Always write the cation and then the anion.NaCl – NEVER ClNaSodium Chloride – NEVER Chloride Sodium

Binary Ionic Nomenclature (Formula Name)

1-State the name of the cation 2-State the name of the anion

For single elements, drop the ending, substitute the suffix –ide

Cl = Chlorine Chloride F = Fluorine Fluoride Br = Bromine Bromide I = Iodine Iodide O = Oxygen Oxide S = Sulfur Sulfide N = Nitrogen Nitride P = Phosphorus Phosphide C = Carbon Carbide

Practice Binary Ionic Naming

CaCl2 – Calcium chloride

MgO – Magnesium oxideAlF3 – Aluminum fluoride

SrBr2 – Strontium bromide

Ba3N2 – Barium nitride

More Key Vocabulary

Subscript – A number that is written smaller and to the lower right of an element or group of elements telling you how many of that element or group there are.H2O Mg(ClO3)2

More Key Vocabulary

Superscript – A number that is written smaller and to the upper right of an element or group of elements telling you the charge of the element or group of elements.H3O+ Ca+2 SO4

-2 N+3

Binary Ionic Nomenclature (Name Formula)

A little more difficult1 - Write the symbol of cation and anion

including charge2 - Use subscripts to balance the charge

of the compound do not need to write a 1 – it is assumedAll ionic compounds have a neutral charge

Binary Ionic Nomenclature (Name Formula)

Calcium Bromide Ca+2 Br-

There is a +2 charge and a -1 chargeAn extra -1 charge is needed Ca+2 Br- Br-

+2 -1 -1 = 0Need 1 calcium and 2 bromine

CaBr2

“Crisscross” Method

Charge of the cation becomes the subscript for anion

Charge of the anion becomes the subscript for the cation

Aluminum Sulfide Al+3 S-2 Al2S3

Notice the + or – charge is dropped

Simplify to smallest whole numbers Mg+2 O-2 Mg2O2 MgO

Check Work

Practice Binary Ionic Formula Writing

Calcium Sulfide – CaSBarium Chloride – BaCl2Lithium Fluoride – LiFAluminum Nitride – AlNSodium Phosphide – Na3P

More Key Vocabulary

Transition Element – An element in group 3 through 12 on the periodic table.

Oxidation State – A possible charge for an ion of a given element. Located in top right corner of element square on PT All “free elements” have oxidation states of ZERO Many elements only have one oxidation state Many (BUT NOT ALL) transition elements have

more than one oxidation state Can have different charges!

Some, but only a few, other metals have multiple oxidation states

More Key Vocabulary

Roman Numerals – A numeral system established in ancient Rome. The system is based on certain letters which combine to signify a number.

1 = I 2 = II 3 = III 4 = IV 5 = V 6 = VI 7 = VII

Binary Ionic Nomenclature Multiple Oxidation States (Formula Name)

Name the CationIn Parenthesis, write the oxidation

number of the cation using Roman Numerals

Name the Anion

Examples: Iron (II) oxide, Iron (III) oxide

Determining Oxidation NumberBased on Formula

We will use the “Multiply Down, Add Across” Method First, rewrite the formula Second, below each element, write the number of

each element Third, write any known charges, or write an “x” for

an unknown charge We typically know the charges for nonmetals

Group 15 = -3 Group 16 = -2 Group 17 = -1

Fourth, multiply down, and then create an algebraic expression so you may add across.

Multiply Down, Add Across

Fe2O3 FeO

2# of each elementKnown

Charges

3

X -2

2X + -6 = 0

Charge of the Compound(Always 0, unless it is an ion)

Solve 2X = +6

X = +3

The oxidation state of Fe is +3

Iron (III) oxide

1 1

X -2

X + -2 = 0

X = +2

The oxidation state of Fe is +2

Iron (II) oxide

Practice Binary Ionic Naming Using Elements w/. Multiple Oxidation States

MnBr4 – Manganese (IV) bromide

CoCl3 – Cobalt (III) chloride

Cr2O3 – Chromium (III) oxide

Ni3N2 – Nickel (II) nitride

TiS2 – Titanium (IV) Sulfide

Check to make sure the oxidation state you think is correct is a possible oxidation state according to your periodic table

Practice Binary Ionic Formula Writing Using Elements w/. Multiple Oxidation States

Easier than namingUse the “crisscross” method

Remember to reduce subscripts…

Manganese (VII) sulfide – Mn2S7

Chromium (VI) phosphide – CrP2

Copper (II) chloride – CuCl2Platinum (IV) Oxide – PtO2

Final Key Vocabulary

Polyatomic Ion – A particle that contains more than one atom and has a positive or negative charge.

Table E

First 3 are cations, the rest are all anions

Ternary Ionic Nomenclature(Formula Name)

Same RulesWrite Cation first, then Anion

Polyatomic Ions have their own endings

NaClO2 = Sodium chlorite

Practice Ternary Ionic Naming

AgNO3 – Silver nitrateCaSO4 – Calcium sulfateNa2S2O3 – Sodium thiosulfateZn3(PO4)2 – Zinc phosphateKMnO4 – Potassium permanganateHg2O – Dimercury (I) oxideNH4Cl – Ammonium chlorideNH4OH – Ammonium hydroxide

Ternary Ionic Nomenclature(Name Formula)

Trickiest of them all… 1 - Write the symbol of cation and anion

including charge This may mean a whole polyatomic ion

2 - Use subscripts to balance the charge of the compound do not need to write a 1 – it is assumed

3 - Any subscripts for a polyatomic ion need to be written outside parenthesis that surround the polyatomic ion.

May still use “crisscross” method

Ternary Ionic Nomenclature (Name Formula)

Aluminum SulfateAl+3 SO4

-2

There is a +3 charge and a -2 chargeWe need 2 +3 charges and 3 +2 chargesAl+3 Al+3 SO4

-2 SO4-2 SO4

-2 +3 +3 -2 -2 -2 = 0Need 2 aluminums and 3 sulfates

Al2(SO4)2

“Crisscross” Method w/. Polyatomic Ions

Charge of the cation becomes the subscript for anion

Charge of the anion becomes the subscript for the cation

Iron (II) hydroxide Fe+2 OH-

YOU NEED PARENTHESIS There are not 2 H’s, there are 2 OH’s

Simplify to smallest whole numbers Ca+2 S2O3

-2 Ca2(S2O3)2

Check WorkFe(OH)2

CaS2O3

Practice Ternary Ionic Formula Writing

Calcium Sulfite – CaSO3

Ammonium sulfide – (NH4)2S

Cobalt (III) phosphate – CoPO4

Copper (II) nitrate – Cu(NO3)2

Ammonium dichromate – (NH4)2Cr2O7

Ionic Nomenclature Mega Practice

Ca3(PO4)2

Calcium phosphate NaOH

Sodium hydroxide FeCl3

Iron (III) chloride CuSO3

Copper (II) sulfite KCN

Potassium cyanide KBr

Potassium bromide

Sodium sulfide Na2S

Barium nitride Ba3N2

Copper (II) peroxide CuO2

Manganese (VII) oxide Mn2O7

Strontium perchlorate Sr(ClO4)2

Chromium (III) nitrite Cr(NO2)3

More Key Vocabulary

Covalent Compounds – contain bonds between one or two nonmetallic elements

Remember when Ionic Bonding was so short and easy, and Covalent Bonding was so long and tough?OPPOSITE HERENaming Covalent Compounds is EASY

Covalent Prefixes

Only hard part: You need to MEMORIZE these prefixes

# atoms Prefix # atoms Prefix

1 -mono 6 -hexa

2 -di 7 -hepta

3 -tri 8 -octa

4 -tetra 9 -nona

5 -penta 10 -deca

Covalent Nomenclature(Formula Name)

Name the elements in the order they are listed

Use the prefixes to show how many of each elementDON’T use “mono” for the first elementAvoid difficulty saying words by eliminating

“ao” or “oo” by just using “o”Hexaoxide is too difficult to say, just write Hexoxide

Change the ending of the second element to -ide

Covalent Nomenclature Practice (Formula Name)

N2O – Dinitrogen monoxide NO2 – Nitrogen dioxide CO – Carbon monoxide CO2 – Carbon dioxide CCl4 – Carbon tetrachloride NI3 – Nitrogen triiodide ***NH3 – Ammonia ***H2O – Water CS2 – Carbon disulfide N2O5 – Dinitrogen pentoxide

*** There are common names for these we use instead, H2O you should know, NH3 is in your reference table…

Covalent Nomenclature (Name Formula)

Even Easier!Use the prefixes to guide you for what

the subscripts need to be

Dihydrogen monosulfideDi = 2 H2

Mono = 1 SH2S

Covalent Nomenclature Practice (Name Formula)

Carbon tetrabromide – CBr4

Iodine dioxide – IO2

Phosphorus pentachloride – PCl5Dichlorine heptoxide – Cl2O7

Diphosphorus trioxide – P2O3

Ionic + Covalent Nomenclature

The trick to naming and formula writing is determine first if the example is an ionic or covalent compound.

P4O10 Dinitrogen monoxide

TiCl3 Ammonium thiosulfate

Calcium Phosphate Ammonia

Ionic

Ionic

Ionic

Covalent

Covalent

Covalent

Tetraphosphorus decoxide

Titanium (III) chloride

Ca3(PO4)2

N2O

(NH4)2S2O3

NH3