Copyright © Houghton Mifflin Company. All rights reserved. 5 | 1 Classifying Binary Compounds Binary ionic compounds contain a metal and a nonmetal. –Type.

Copyright © Houghton Mifflin Company. All rights reserved. 5 | 1

Classifying Binary Compounds

• Binary ionic compounds contain a metal and a nonmetal.– Type I and II

• Compounds containing two nonmetals– Type III

• Compounds containing H and a nonmetal = Acids


Metal Cations

• Type I – Metals that can only have one possible charge– Charge determined by position on the Periodic

Table (group 1A: +1; group 2A: +2)

• Type II– Metals that can have more than one possible

charge (transition metals)– Metal cation’s charge (usually +1, +2, +3, or

+4) determined from the charge on anion


The Modern Periodic Table


Type I Binary Ionic Compounds

• Contain Metal Cation from Groups 1A, 2A or Al, Ga, & In (metals with only one possible ionic charge) + Nonmetal Anion

• Metal listed first in formula & name• Name metal cation first, name nonmetal

anion second• Nonmetal anion named by changing the ending on

the nonmetal name to –ide


Name the following Type I Compounds:

You must know the simple cations and anions in Table 5.1

• MgCl2

• K2O

• CaBr2

• BaS


Type II Binary Ionic Compounds

• Metal cation name is the metal name followed by a Roman numeral in parentheses to indicate its charge– Determine charge from anion charge– Common Type II cations in Table 5.2

• Nonmetal anion named by changing the ending on the nonmetal name to -ide


Determining the Charge on a Cation – Au2S3

• Determine the charge on the anion– Au2S3: the anion is S, since it is in Group 6A, and its charge is

–2• Determine the total negative charge

– Since there are 3 S in the formula, the total negative charge is –6

• Determine the total positive charge– Since the total negative charge is -6, the total positive charge is

+6• Divide by the number of cations

– Since there are 2 Au in the formula & the total positive charge is +6, each Au has a +3 charge


Name the following Type II compounds:

• CrCl3

• CrCl2

• Cu2O

• CuO

• Fe2S3


Type III - Binary Compounds of Two Nonmetals

• Name first element in formula first. Use the full name of the element.

• Name the second element in the formula as if it were an anion.

– However, remember these compounds do not contain ions!

• Use a prefix in front of each name to indicate the number of atoms.

• Never use the prefix mono- on the first element.


Prefixes

• Drop last “a” in the prefix if the name begins with vowel: N2O5 dinitrogen pentoxide (not pentaoxide)

octa-8

hepta-7

hexa-6

penta-5

tetra-4

tri-3

di-2

mono- (not used on first nonmetal)1

PrefixSubscript


Name the following Type III compounds:

• CCl4

• N2O3

• PCl3

• PCl5

• CO


Roadmap for Naming Binary Compounds


Classify and name the following binary compounds:

• OCl2

• CaBr2

• CuS

• B2O3


Compounds Containing Polyatomic Ions

• Polyatomic ions are charged entities that contain more than one atom (e.g. HSO4

-)– Must memorize name, formula, and charge– Table 5.4

• Polyatomic compounds contain one or more polyatomic ions.

• To name these compounds you must learn to recognize the polyatomic ions.

(NH4C2H3O2) ammonium acetate


Compounds Containing Polyatomic Ions (cont.)

• Name polyatomic compounds by naming cation and anion.– Non-polyatomic ions named like Type I and II

Na2SO4 sodium sulfate

• Polyatomic acids contain H+ and a polyatomic anion.


Names of Common Polyatomic Ions


Oxyanions

• -ate ion– chlorate = ClO3

-

• -ate ion plus 1 O same charge, per- prefix– perchlorate = ClO4

-

• -ate ion minus 1 O same charge, -ite suffix– chlorite = ClO2

-

• -ate ion minus 2 O same charge, hypo- prefix, -ite suffix– hypochlorite = ClO-


Patterns for Polyatomic Ions

• Elements in the same column on the periodic table form similar polyatomic ions.

– Same number of O’s and same charge

ClO3- = chlorate BrO3

- = bromate

• If the polyatomic ion starts with H, add hydrogen- before the ion’s name and add one to the charge.

CO32- = carbonate HCO3

- = hydrogen carbonate


Name the following compounds:

• Na3PO4

• FeCO3

• (NH4)2CO3

• Ca(CN)2


Naming Acids

• Formulas always begin with H as first element

• Can be thought of as consisting of H+ cation and anion

• Binary acids have H+ cation and a nonmetal anion

• Oxyacids have H+ cation and a polyatomic anion


Naming Acids (cont)

• If the anion does not contain oxygen, use the prefix hydro- plus the suffix –ic attached to the root name of the element followed by the word acid.

• HBr:• When the anion contains oxygen, use the root name of the

central element of the anion, with a suffix –ic or –ous, followed by the word acid. When the anion name ends in -ate, the suffix –ic is used. When it ends in –ite, the suffix –ous is used.

• H2SO4:• H2SO3:• HNO3:• HNO2:


Naming Acids (Summary)


Writing Formulas from Names

• For Type I, Type II, polyatomic compounds and acids:

– Determine the ions present.– Determine the charges on the cation and anion.– Balance the charges to get the subscripts.

• For Type III compounds, use the prefixes to determine the subscripts.


Write the formula for each of the following compounds:

• diboron trioxide

• copper(III) bromide

• chromium (II) permanganate

• phosphorus tribromide

Copyright © Houghton Mifflin Company. All rights reserved. 5 | 1 Classifying Binary Compounds Binary ionic compounds contain a metal and a nonmetal. –Type.

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