CHEMICAL NAMES CHEMICAL NAMES & FORMULAS& FORMULAS

To describe the atomic To describe the atomic makeup of compounds, makeup of compounds, chemists use systematic chemists use systematic

methods for naming methods for naming compounds and writing compounds and writing

formulas.formulas.

Chemical FormulasChemical Formulas Subscript directly behind an atom Subscript directly behind an atom

applies to that atom only. applies to that atom only. HH22OO

Subscripts outside of parentheses Subscripts outside of parentheses applies to all atoms inside the applies to all atoms inside the parentheses.parentheses.

AlAl22(SO(SO44))33

Monatomic IonsMonatomic Ions Ions formed from a single atom.Ions formed from a single atom. Written as element symbol w/charge Written as element symbol w/charge

as superscript.as superscript. Monatomic Monatomic cations (+)cations (+)

• simply simply element’s nameelement’s name.. Monatomic Monatomic anions (-)anions (-)

• ending of element’s name is dropped.ending of element’s name is dropped.• ending –ide is added.ending –ide is added.

Examples of Monatomic IonsExamples of Monatomic Ions

Write formulas for the following Write formulas for the following monatomic ions:monatomic ions:LithiumLithium NitrideNitride

BromideBromide Iron (II)Iron (II) Write names for the following Write names for the following

monatomic ions:monatomic ions:BaBa2+2+ SnSn4+4+ SS2-2-

ClCl-- MgMg2+2+ CuCu2+2+

Binary Ionic CompoundsBinary Ionic Compounds Composed of 2 different elements. Composed of 2 different elements.

Total (+) and (-) charges must be Total (+) and (-) charges must be equal.equal.• Magnesium Flouride MgMagnesium Flouride Mg2+2++ F+ F- - = MgF= MgF22

Must have 2 (-) F’s to equal (+) 2 charge of Must have 2 (-) F’s to equal (+) 2 charge of Mg.Mg.

Charges Crossover.Charges Crossover. To name combine names of cation To name combine names of cation

and anion with cation being first.and anion with cation being first.• ZnSZnS Zinc SulfideZinc Sulfide

Binary Ionic Compound Binary Ionic Compound ExamplesExamples

Write the formula for the binary ionic compounds Write the formula for the binary ionic compounds formed between the following elements:formed between the following elements:Zinc & IodineZinc & Iodine Zinc & SulfurZinc & Sulfur

Sodium & OxygenSodium & Oxygen Calcium & NitrogenCalcium & Nitrogen

Name the binary ionic compounds indicated by Name the binary ionic compounds indicated by the following formulas:the following formulas:AgClAgCl CaBrCaBr22

BaOBaO ZnOZnO

SrFSrF22 CaClCaCl22

Stock System of Stock System of NomenclatureNomenclature

System used to distinguish between System used to distinguish between cations of elements that form more cations of elements that form more than one cation. Uses Roman than one cation. Uses Roman Numerals.Numerals.• CuClCuCl22 Copper (II) ChlorideCopper (II) Chloride

Examples of Stock System Examples of Stock System of Nomenclatureof Nomenclature

Write the formula and give the name Write the formula and give the name of the compounds formed between of the compounds formed between the ions:the ions:CuCu2+2+ & Br & Br--

FeFe3+3+ & O & O2-2-

Give the names for the following Give the names for the following compounds:compounds:CuOCuO CoFCoF33

SnISnI44 FeSFeS

Polyatomic IonsPolyatomic Ions Most CommonMost Common -ate-ate 1 Less O1 Less O -ite-ite 2 Less O’s2 Less O’s hypo-hypo- 1 More O1 More O per-per-

Compounds Containing Compounds Containing Polyatomic IonsPolyatomic Ions

Same as Binary Ionic CompoundsSame as Binary Ionic Compounds Name of Cation given 1Name of Cation given 1stst, Name , Name

of Anion 2of Anion 2ndnd. . When Writing formula, put When Writing formula, put

parentheses around anion if parentheses around anion if more than one is present in the more than one is present in the compound.compound.

Examples of Compounds Examples of Compounds Containing Polyatomic IonsContaining Polyatomic Ions

Write the formula for the following:Write the formula for the following:Tin (IV) SulfateTin (IV) Sulfate Calcium NitriteCalcium Nitrite

Sodium IodideSodium Iodide Copper (II) SulfateCopper (II) Sulfate Give the name for the following Give the name for the following

compounds:compounds:AgAg22OO Ca(OH)Ca(OH)22

KClOKClO33 NHNH44OHOH

KClOKClO FeCrOFeCrO44

Naming Binary Naming Binary Molecular CompoundsMolecular Compounds

Unlike ionic compounds, molecular Unlike ionic compounds, molecular compounds are composed of individual compounds are composed of individual covalently bonded units.covalently bonded units.

Scientists use 2 systems to name these Scientists use 2 systems to name these compounds, the 1compounds, the 1stst uses prefixes. uses prefixes.

Rules for the Prefix SystemRules for the Prefix System1.1. The less-electronegative element is The less-electronegative element is

given 1given 1stst. It is given a prefix only if . It is given a prefix only if it contributes more than 1 it contributes more than 1 molecule.molecule.

2.2. 22ndnd element is named by: element is named by: Prefix indicating # of atomsPrefix indicating # of atoms Root of the elementRoot of the element The ending –ideThe ending –ide

3.3. When a prefix is used and the root When a prefix is used and the root begins w/a vowel, the o or a of the begins w/a vowel, the o or a of the prefix is dropped.prefix is dropped.

General Electronegativity OrderGeneral Electronegativity Order

C, P, N, H, S, I, Br, Cl, O, FC, P, N, H, S, I, Br, Cl, O, F

Mono is normally omitted on 2Mono is normally omitted on 2ndnd element.element.

Binary Molecular Compound Binary Molecular Compound ExamplesExamples

Name the following Binary Molecular Name the following Binary Molecular Compounds:Compounds:SOSO33 IClICl33 PBrPBr55

Write formulas for the following Write formulas for the following compounds:compounds:• Carbon TetraiodideCarbon Tetraiodide• Phosphorus TrichloridePhosphorus Trichloride• Dinitrogen TrioxideDinitrogen Trioxide

Oxidation NumbersOxidation Numbers Used in New System – Stock SystemUsed in New System – Stock System

Same as Stock System used for Same as Stock System used for Binary Ionic Compounds.Binary Ionic Compounds.

Roman Numeral is used for Oxidation Roman Numeral is used for Oxidation Number of 1Number of 1stst element in a element in a compound. 2compound. 2ndnd element is named element is named with name ending in –ide.with name ending in –ide.

AssignmentAssignmentPage 236Page 236

(#’s: 27, 28, & 29)(#’s: 27, 28, & 29)

Using Using Chemical Chemical FormulasFormulas

Formula MassFormula Mass Sum of all the average atomic Sum of all the average atomic

masses of all the atoms masses of all the atoms represented in a formula unit.represented in a formula unit.

Round to 2 decimal places.Round to 2 decimal places.

Calculating Formula MassCalculating Formula MassAverage Atomic Mass H:Average Atomic Mass H:

1.01 amu1.01 amuAverage Atomic Mass O:Average Atomic Mass O:

16.00 amu16.00 amu2H atoms X 1.10amu/H atom =2H atoms X 1.10amu/H atom =

2.02 amu2.02 amu1O atom X 16.00amu/O atom =1O atom X 16.00amu/O atom =

16.00 amu16.00 amu

Average Atomic Mass HAverage Atomic Mass H22O:O: 2.02 amu + 16.00 amu =2.02 amu + 16.00 amu =

18.02 amu H18.02 amu H22OO

Find the Formula Mass for Find the Formula Mass for each of the following:each of the following:

Potassium ChloratePotassium Chlorate

Sulfuric AcidSulfuric Acid

Calcium NitrateCalcium Nitrate

Phosphate IonPhosphate Ion

Magnesium ChlorideMagnesium Chloride

AssignmentAssignmentPage 236Page 236

(# 30)(# 30)

Molar MassMolar Mass