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 Ion 2 atoms of same element H2, O2, N2, F2, Cl2, Br2, I2 Polyatomic 3 or more atoms of same element Sulfur (S8) and Phosphorus (P4) Ion Charged particle Positive (cation) Negative (anion) IUPAC – international union of pure and applied chemistry 1921 – still meets regularly Diatomic – just normal name Polyatomic – more than 2 ion

Elements and Ions Naming cations Naming anions 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 Need to know figure 6.2 by memory Should be familiar after chapter 11

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 Aluminum and oxygen Na1+ Cl1- NaCl Al2O3 Al3+ O2-

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 P3- Formula is Ba3P2 Sodium sulfide Sodium will form Na+ Sulfur will form S2- Formula 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- Calcium sulfide Calcium is Ca2+ and Sulfur is S2- SrCl2 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 CuCl2 Tin (IV) Oxide is SnO2 -ous and –ic endings are also sometimes used -ous and –ic endings are OLD SYSTEM – should know common ones such as iron and copper…others almost always listed in Stock System Ferrous = 2+ Ferric = 3+ Cuprous = + Cupric = 2+

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 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 CBr4 NH3 Diphosphorus pentoxide 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 Not ALL hydrogen compounds form acids – methane (CH4), ammonia (NH3) – H written after another

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 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 NO3- Nitrite is NO2- Hypo- (if more than two varieties) ClO- hypochlorite ClO2- chlorite ClO3- chlorate ClO4- 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” See figure 6.5 page 120 HC2H3O2 Hydrogen & acetate ion Acetic acid

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