[chem] Chem Nomenclature

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  



Polyatomic  



2 atoms of same element H2, O2, N2, F2, Cl2, Br2, I2 3 or more atoms of same element Sulfur (S8) and Phosphorus (P4)

Ion   

Charged particle Positive (cation) Negative (anion)

Elements and Ions 

Naming cations  



Naming anions 

 



Same as element but add the word ion Potassium ion 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

Na1+ 

Cl1-

NaCl

Aluminum and oxygen

Al3+

O2-

Al2O3

Writing Formulas from Names of Compounds 

Write formulas for the following 

Calcium chloride Calcium will form Ca2+  Chlorine will form Cl1





Formula is CaCl2

Magnesium oxide Magnesium will form Mg2+  Oxygen will form O2



Formula is MgO

Writing Formulas from Names of Compounds 

Barium phosphide   



Barium will form Ba2+ Phosphorus will form P3Formula is Ba3P2

Sodium sulfide   

Sodium will form Na+ Sulfur will form S2Formula is Na2S

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 Sr2+ and Chlorine is Cl-

SrCl2

Calcium sulfide 

Calcium is Ca2+ and Sulfur is S2-

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 Fe2+ or Fe3+

Stock System Use Roman Numeral to designate charge of cation  Copper (II) Chloride is CuCl 2 





Tin (IV) Oxide is SnO2

-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 

PbI2



Fe2O3

 

CuO TiF4

Lead (II) Iodide Iron (III) Oxide Copper (II) Oxide 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

Meaning

Prefix

Meaning

Mono

1

Hexa

6

Di

2

Hepta

7

Tri

3

Octa

8

Tetra

4

Nona

9

Penta

5

Deca

10

Binary Compounds Containing Two Nonmetals 



Examples: 

N2O is dinitrogen monoxide (drop “o”)



S2F10 is disulfur decofluoride

You try:   

P2O5

Diphosphorus pentoxide

CBr4

Carbon tetrabromide

NH3

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 hydroAdd suffix –ic Add the word acid

Acids Derived from Binary Compounds 

H2S  



Hydrogen sulfide (if not in water) Hydrosulfuric acid

HCl  

Hydrogen chloride (if not in water) Hydrochloric 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) 

ClO- hypochlorite



 



-ate indicates -ite indicates 

Nitrate is NO3-



Nitrite is NO2-

Hypo

(if more than two varieties)

ClO2- chlorite ClO3- chlorate ClO4hyperchlorate 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  HC H O 2 3 2 



Add the word “acid”

Hydrogen & acetate ion Acetic acid 

Homework    

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