Nomenclature Chapter 9

Chemical Formula Chemical Formulas tell two things: Letters = elements Subscripts = # of atoms of each element Ex. Fe2O3 2 iron atoms & 3 oxygen atoms CaCO3  # elements? # atoms? Al2(SO4)3  # elements? 3 5 3 17

Compounds Binary compound  has 2 elements Ex. NaCl Ternary compound  has 3 elements NaNO3

Review of Ionic Compounds Attraction of (+) and (-) ions. (transfer e-) Metal loses e-  (+) Nonmetal gains e-  (-) Cation (metal) is written FIRST!! The OVERALL charge of the compound is ZERO.

Binary Ionic Names How do you know it’s binary ionic? metal + nonmetal Rules: 1) Name the first element as it is on the periodic table. 2) Change the ending of the second element to “ide”. 3) Check if the metal is a transition metal. If so, figure out the charge on it and use Roman numerals to show the CHARGE.

Binary Ionic Naming Examples sodium bromide NaBr  CaCl2  Cu2O  Fe2O3  K2S  Sr3P2  CoBr  Mn3N  calcium chloride copper (I) oxide iron (III) oxide potassium sulfide strontium phosphide cobalt (I) bromide manganese (I) nitride

Binary Ionic Naming Exceptions Lead (Pb) and Tin (Sn) are not transition metals, but THEY DO NEED ROMAN NUMERALS!! Silver (Ag) and Zinc (Zn) are transition metals, but DO NOT NEED ROMAN NUMERALS! Sliver is ALWAYS +1 Zinc is ALWAYS +2

Binary Ionic Formulas Rules: 1) Write the element symbols. 2) Write the oxidation #s (charges). * If it’s a transition metal, you won’t know the charge – so look at the Roman numeral! 3) Criss-cross the charges down. 4) Simplify the ratio if needed.

Binary Ionic Formula Examples Write the formula for each name: copper (II) oxide zinc bromide copper (I) oxide barium chloride lead (IV) sulfide calcium nitride iron (III) sulfide aluminum fluoride silver oxide CuO ZnBr2 Cu2O BaCl2 PbS2 Ca3N2 Fe2S3 AlF3 Ag2O

Ternary Ionic Compounds Involve polyatomic ions (group of atoms with an overall charge) Most polyatomic ions have “ite” or “ate”, meaning oxygen is in it. Treat the polyatomic ion as a unit and never change its name!! (Don’t use “ide” for it.) Put polyatomic ions in parentheses unless the subscript is 1. NEVER change the subscripts within the polyatomic ion!!

Naming Ternary Ionic Compounds 1) Name the (+) ion. 2) Name the (-) ion (no “ide” if it’s a polyatomic ion!). 3) Use Roman numerals if the metal is a transition metal, lead or tin.

Name Ternary Ionic Examples ammonium hydroxide NH4OH KNO3 MnSO4 Cu(NO3)2 Fe2(CO3)3 Co(OH)2 potassium nitrate manganese (II) sulfate copper (II) nitrate iron (III) carbonate cobalt (II) hydroxide

Writing Formulas for Ternary Ionic Compounds Use the same criss-cross method as with binary compounds. Remember to use ( ) if the subscript of a polyatomic ion is more than 1! (Watch out for hydroxide!)

Ternary Ionic Formula Examples Write the formula for each: aluminum carbonate ammonium phosphate tin (IV) sulfate sodium nitrite zinc hydroxide potassium sulfite Al2(CO3)3 (NH4)3PO4 Sn(SO4)2 NaNO2 Zn(OH)2 K2SO3

Molecular Compounds Review of Molecular Compounds: Involves a sharing of e- Molecules can exist independently Covalently bonded How do you know it’s molecular? All nonmetals!

Naming Molecular Compounds Use prefixes to indicate the number of atoms. 1 Exception: Do NOT begin a name with “mono”. Change the ending of the second element to “ide”. mono 1 hexa 6 di 2 hepta 7 tri 3 octa 8 tetra 4 nona 9 penta 5 deca 10

Naming Molecular Compounds - Examples N2O carbon monoxide carbon dioxide diphosphorous pentoxide tetraphosphorous decoxide dinitrogen monoxide

Molecular Formulas The prefix tells you what subscript to write. Remember if there is no prefix for the first element, it is “mono”.

Molecular Formula Examples dinitrogen monoxide sulfur trioxide dinitrogen pentoxide nitrogen trihydride pentaphosphorous decoxide N2O SO3 N2O5 NH3 P5O10

When you look at a compound: First – Decided if it’s ionic or molecular!! * Ionic m – nm polyatomic ions * Molecular nm - nm

Acids What is an acid? How do you know something is an acid? An aqueous solution (in water) of hydrogen compounds How do you know something is an acid? It starts with H

Binary Acids Binary acid  Includes H + one other element. (Ex. HBr) To name: “hydro ic acid”

Naming Binary Acid Examples HCl HBr H2S hydrochloric acid hydrobromic acid hydrosulfuric acid

Binary Acid Formulas Don’t forget to use the criss-cross method! Examples: hydroiodic acid hydrofluoric acid hydrophosphoric acid HI HF H3P

Ternary Acids Ternary acid  H + polyatomic ion. (Ex. HNO3) If the polyatomic ion’s name ends in “ate”, the acid’s name ends in “ic”. (I “ate” it and it made me s”ic”k.) If the polyatomic ion’s name ends in “ite”, the acid’s name ends in “ous”.

Naming Ternary Acids phosphoric acid sulfurous acid sulfuric acid H2CO3 HNO2 HNO3 H3PO4 H2SO3 H2SO4 carbonic acid nitrous acid nitric acid

MEMORIZE THESE!! Hydrochloric acid – HCl Nitric acid – HNO3 Sulfuric acid – H2SO4 Acetic acid – HC2H3O2 or CH3COOH