Ch. 4 Notes---Nomenclature: Chemical Names & Formulas

• Ionic Compounds (“________”):

– Name or formula starts with a _________ (or NH4 +, ammonium).

– Other quick ways to tell if the compound is ionic:

• formula uses parentheses

Example: ________________

• formula contains more than 2 elements (capital letters)

Example: ________________

• name uses Roman numerals

Example: ________________

• name ends in “-ate” or “ite”.

Example: _________________

salts

metal

Ca(OH)2

FeCrO4

lead(II) chloride

barium sulfate

• Molecular Compounds (“____________”):

– Name or formula starts with a ____________ (exception: NH4 +)

– Other quick ways to tell if the compound is molecular:

• Name has prefixes and also ends in “-ide”. (It must have both!)

Examples: _________________,_______________________

Naming Ionic Compounds

• Just use your ion sheet and find the names of the ions.

cation name anion name

Practice Problems: Name the following ionic compounds.

a) NaC2H3O2 b) (NH4)2CO3 c) Fe(OH)3 d) PbSO4

molecules

nonmetal

carbon dioxide dinitrogen pentoxide

sodium ammonium ironacetate carbonatehydroxide

(III) leadsulfate

(II)

Writing Formulas for Ionic Compounds

• Step 1-- Use your ion sheet and find the ions and their charges.

• Step 2-- “Cross the charges” if they don’t balance out.

• Step 3-- Use parentheses around polyatomic ion “chunks”.

Practice Problems: Write the formula for each ionic compound.

copper(II) bromide ____________________

aluminum nitrite _________________________

barium hydrogen carbonate ___________________________

Cu+2 Br -1 = CuBr2…(don’t show 1’s)

Al+3 NO2 -1 = Al(NO2)3

Ba+2 HCO3-1 = Ba(HCO3)2

Naming Molecular Compounds

• You do not use the ion sheet for molecules because no __________ are needed. They ______________ electrons instead of transferring them.

• Use ________________ to indicate the # and kind of atom in the compound.

mono=1 di=2 tri=3 tetra=4 penta=5 hexa=6 hepta=7 octa=8 non=9 deca=10

• Use the general format shown below…

prefix-(except mono)-name the 1st element prefix-name the 2nd element ending with -ide

Practice Problems: Name the following molecules.

N2O5 CO Cl4F7 SO3

chargesshare

prefixes

dinitrogen pentoxide

carbon monoxide

tetrachlorine heptafluoride

sulfur trioxide

Writing Molecular Formulas

• The prefixes in the name tell you the # of atoms of each element there are. (Those become the _________________ in the formula!)

Practice Problems: Write the formula for each molecule.

nitrogen monoxide carbon tetrachloride diphosphorous pentoxide

Acids

• All acids begin with the element ________________.

• General format: H(X), where “(X)” represents the ______________.

• There are 2 general types of acids:

– If the name of “(X)” ends in –ite or –ate, then it is an _________ acid.

– If the name of “(X)” ends in –ide, then it is a ____________ acid. The acids

just contains ____ elements, hydrogen and a nonmetal. (There’s NO oxygen!)

subscripts

NO CCl4 P2O5

hydrogen

anion

oxy-

binary2

Naming Oxy-Acids

1. If the name of “(X)” ends in –ate… (anion root)-ic acid

2. If the name of “(X) ends in –ite… (anion root)-ous acid

Practice Problems: Name these acids.

H2SO4 H3PO3 HNO3 H2CO3 HC2H3O2

HClO2

Naming Binary Acids

If the name of “(X)” ends in –ide… hydro- (anion root)-ic acid

Practice Problems: Name these acids.

H2S HCl HF

sulfuric acid

phosphorous acid

nitric acid

carbonic acid

acetic acid

chlorous acid

hydrosulfuric acid hydrochloric acid hydrofluoric acid

Writing the Formulas for Acids

FIRST You must determine the formula for the anion, “(X)”.

1. If the acid’s name starts with “________” (and ends in “–ic”), the name of the anion used ends in “_______”. Therefore, it is a _________ acid. (There’s only hydrogen and one other nonmetal in the formula!)

• The subscript on the hydrogen equals the anion’s charge!

Examples: hydrobromic acid = ________

hydroiodic acid = _______

hydrosulfuric acid = ________

hydro-ide

binary

HBr

HI

H2S

2. If the acid’s name ends with “______” without the “hydro-” prefix, the name of the anion used ends in “_______”. Therefore, it is an ____ acid.

• The subscript on the hydrogen equals the anion’s charge!

Examples: perchloric acid = __________

oxalic acid = ___________

3. If the acid’s name ends with “______”, the name of the anion used ends in “_______”. (It’s is also an oxy-acid.)

• The subscript on the hydrogen equals the anion’s charge!

Examples: hypochlorous acid = __________

nitrous acid = ____________

sulfurous acid = ____________

-ic-ate

oxy-

HClO4

H2C2O4

-ous-ite

HClO

HNO2

H2SO3