Chapter 6

Nomenclature of Inorganic Compounds

Objectives:

 Distinguish between common and systematic names of compounds  Review differences between elements and ions  Be able to write formula from names of compounds  Understand binary compounds  Name compounds containing polyatomic ions  Name and recognize acids

Common and Systematic Names

 Common Names  Arbitrary  Not based on chemical composition  Historically associated with a physical or chemical property  Not consistent among languages or disciplines  Systematic names  Identify the chemical composition  Devised by IUPAC

Elements and Ions

 Diatomic molecules   2 atoms of same element  H 2 , O 2 , N 2 , F 2 , Cl 2 , Br 2 , I 2 Polyatomic  3 or more atoms of same element   Ion Sulfur (S 8 ) and Phosphorus (P 4 )  Charged particle  Positive (cation)  Negative (anion)

Elements and Ions

 Naming cations  Same as element but add the word ion  Potassium ion  Naming anions  Stem of the parent name with ending changed to

– ide

 Add the word ion  Oxide ion  Commonly formed ions – figure 6.2 pg 107

Writing Formulas from Names of Compounds

 Chemical compounds

must have

a net charge of

zero

 Compare charges of ions formed from elements  “Trade” charges and rewrite as subscript on opposite ion  Write with lowest possible whole numbers

Writing Formulas from Names of Compounds

 Write formulas for  Sodium and chlorine Na 1+ Cl 1 NaCl  Aluminum and oxygen Al 3+ O 2 Al 2 O 3

Writing Formulas from Names of Compounds

 Write formulas for the following  Calcium chloride  Calcium will form Ca 2+  Chlorine will form Cl 1  Formula is

CaCl 2

 Magnesium oxide  Magnesium will form Mg 2+  Oxygen will form O 2  Formula is

MgO

Writing Formulas from Names of Compounds

 Barium phosphide  Barium will form Ba 2+  Phosphorus will form P 3   Formula is

Ba 3 P 2

Sodium sulfide  Sodium will form Na +  Sulfur will form S 2  Formula is

Na 2 S

Binary Compounds

 Contain only two different elements  Often metal with nonmetal (binary ionic compound)

Binary Ionic Compounds Containing a Metal Forming Only One Type of Cation

 Name of cation is left the same  Name of anion is changed (-ide)  Write formulas for the following compounds  Strontium chloride  Strontium is Sr 2+ and Chlorine is Cl SrCl 2  Calcium sulfide  Calcium is Ca 2+ and Sulfur is S 2 CaS

Binary Ionic Compounds Containing a Metal That Can Form Two or More Types of Cations

 Metals in the center of the periodic table  Iron can be Fe 2+ or Fe 3+  Stock System  Use Roman Numeral to designate charge of cation  Copper (II) Chloride is CuCl 2  Tin (IV) Oxide is SnO 2  -ous and –ic endings are also sometimes used

Binary Ionic Compounds Containing a Metal That Can Form Two or More Types of Cations

 Write the name for each of the following compounds Lead (II) Iodide  PbI 2  Fe 2 O 3  CuO Iron (III) Oxide Copper (II) Oxide  TiF 4 Titanium (IV) Fluoride

Binary Compounds Containing Two Nonmetals

 Not ionic bonds -

Molecular (covalent)



Different system of naming

 Element that occurs first in the series below is written and named first  Si, B, P, H, C, S, I, Br, N, Cl, O, F  Usually given to you…first element listed always named first  Second element retains –ide ending

Binary Compounds Containing Two Nonmetals

 Prefix is attached to each element to indicate the number of atoms of that element in the molecule  Mono (1) never used for first element

Prefix

Mono Di Tri Tetra Penta 3 4 5

Meaning

1 2

Prefix

Hexa Hepta Octa Nona Deca

Meaning

6 7 8 9 10

Binary Compounds Containing Two Nonmetals

 Examples:  N 2 O is dinitrogen monoxide (drop “o”)  S 2 F 10 is disulfur decofluoride  You try: Diphosphorus pentoxide  P 2 O 5  CBr 4  NH 3 Carbon tetrabromide Nitrogen trihydride

Acids Derived from Binary Compounds

 Hydrogen compounds – form acids in water  Write symbol of H first, then the rest  Shows it is an acid  Naming  Take stem of nonmetal   Add prefix

hydro-

Add suffix

–ic

 Add the word

acid

Acids Derived from Binary Compounds

 H 2 S  Hydrogen sulfide (if not in water)  Hydro sulfur ic acid  HCl  Hydrogen chloride (if not in water)  Hydro chlor ic acid

Figure 6.4 on page 115 VERY HELPFUL FOR NAMING BINARY COMPOUNDS

Naming Compounds Containing Polyatomic Ions

 Polyatomic ion    Must be able to recognize common polyatomic ions  Table 6.6 (pg 116)

Naming Compounds Containing Polyatomic Ions

 Usually end in –ate or –ite (but not always)   

-ate

indicates 

-ite

indicates  

Nitrate is NO 3 Nitrite is NO 2 -



Hypo-

 (if more than two varieties) ClO hypochlorite ClO 2 chlorite ClO 3 chlorate ClO 4 hyperchlorate or perchlorate

Naming Compounds Containing Polyatomic Ions

 Need to recognize polyatomic ions in Table 6.6



Hydroxide (OH )

 

Cyanide (CN )

 

Naming Compounds Containing Polyatomic Ions

 Naming follows binary compound rules 

Naming Acids

 Oxy-acids  Inorganic compounds containing hydrogen, oxygen, and one other element    Change ending of polyatomic ion    Add the word “acid” 

HC 2 H 3 O 2



Hydrogen & acetate ion



Acetic acid

Homework

 Questions #1,3,6  Paired Exercises #7-25 odd   Additional Exercise #34 & 36 Remember: Quiz next class 