NH 4 Cl Na + SO 4 2–

Nomenclature Some things ya just gotta know –Ion nomenclature is one of those things Classifying your ions can help you learn them –By charge –By type (monatomic or polyatomic) –By common things in their names

Monatomic Ions-Metal Ions All metal ions are cations (+ charge) Metal ions carry the name of the element, followed by the term, “ion” Metals that form only one ion do not require Roman numerals –Group I metals form ions with +1 chg –Group II metals form ions with +2 chg –Al 3+, Zn 2+, Ag +

Ions with Multiple Charges Metals that form multiple ions require Roman numerals –Roman numeral identifies the charge Cu + = copper (I) ion Cu 2+ = copper (II) ion –All transition metals except Al, Zn, and Ag commonly form multiple ions

Monatomic Ions-Nonmetal Ions Nonmetal ions are anions (– chg) Nonmetal ions carry the root of the nonmetal element, ending in -ide Cl – = chlorine ion ide S 2– = sulfide ion

Monatomic Ions-Nonmetal Ions Ion charge is determined by position on the periodic table –Periodic Table: “1 2 3 skip 3 2 1” Halogens: –1 charge Alkali metals: +1 charge Alkaline earth metals: +2 charge

Polyatomic Ions Most polyatomic ions are anions –Exception: ammonium ion (NH 4 + ) Most polyatomic ions contain oxygen –Known as oxyanions Names vary, but often follow a pattern *mnemonics

NSP 123

Nitrogen Sulfur Phosphorus – 1 – 2 – 3

–1 –2 –3 N S P Nitrate Sulfate Phosphate

NSP 344344 Element Charge (  ) Oxygens Formula NO 3  SO 4 2  PO 4 3 

ClO 3  ClO 4  chlorate perchlorate Su

Names and Formulas of Ionic Compounds

We will use the formulas of compounds to tell their names and... We will use the names of compounds to write their formulas

A chemical formula... Represents the composition of one molecule of a molecular compound -- or-- Represents one formula unit of an ionic compound

A chemical formula... Shows the experimentally determined composition Can represent an amount of substance – One molecule – One mole of molecules – One molar mass

Formulas of Ionic Compounds All compounds are electrically neutral Ionic compounds are formed by simply combining positive and negative ions

Formulas of Ionic Compounds Ions must be combined so that total positive charges equal total negative charges Formula unit is the simplest combination where total positive charge equals total negative charge

The “Criss-Cross” Method Make the charge of one ion the subscript of the other ion Simplify (if possible) Remember: subscripts can never have a negative sign

The “Criss-Cross” Process Write formula of each ion –Cation first, then anion Put ( ) around any polyatomic ions –Ion charge is outside ( ) –Formula subscripts are inside ( )

The “Criss-Cross” Process “Criss-cross” the charges –Absolute value of charge of one ion becomes subscript of the other Can’t have negative subscripts! –New subscript must go outside ( ) of any polyatomic ion

The “Criss-Cross” Process Reduce subscripts to simplest terms –No subscript of 1 –The ( ) go away if the subscript outside ( ) is 1

The “Criss-Cross” Method K+K+ Br¯ 11 K 1 Br 1 KBr

The “Criss-Cross” Method K+K+ (SO 4 ) 2– 2 1 K 2 (SO 4 ) 1 K 2 SO 4

The “Criss-Cross” Method Fe 3+ (SO 4 ) 2– 2 3 Fe 2 (SO 4 ) 3

The “Criss-Cross” Method Fe 2+ (SO 4 ) 2– 2 2 Fe 2 (SO 4 ) 2 FeSO 4 Reduce subscripts to simplest ratio

Ionic Formulas Process Summary Write ion formulas and charges –Cation on left; anion on right Put parentheses () around poly-atomic ions “Criss-cross” charges –Absolute value only –Put new subscript outside parentheses –Reduce

Naming Ionic Compounds Name the positive ion (cation) first (include Roman numerals) Name the negative ion (anion) second –Doesn’t matter whether the ions are monatomic or polyatomic

Naming Ionic Compounds NaCl FeSO 4 sodiumchloride iron (?)sulfate Iron forms more than 1 ion. Which iron ion is this?

FeSO 4 Fe 1 (SO 4 ) 1 Fe 1 ? (SO 4 2– ) 1 1 ·(–2) = –2+2 Fe 2+ SO 4 2– iron (II)sulfate 1 · (?) =

Naming Ionic Compounds Stock system CuCl 2 = copper (II) chloride SnF 2 = tin (II) fluoride Fe(NO 3 ) 3 = iron (III) nitrate PbO = lead (II) oxide

Naming Ionic Compounds The “Old” System of naming multiple-charged ions CuCl 2 = cupric chloride SnF 2 = stannous fluoride Fe(NO 3 ) 4 = ferric nitrate PbO = plumbous oxide

Names and Structures of Acids All acids are binary acids or oxyacids Binary acids –Contain hydrogen and one other element –All are “hydro-icky” “-ide” ion

Names and Structures of Acids Oxyacids –Contain hydrogen, oxygen, and a third element –Name determined by the polyatomic ion in formula “-ates” become “-ic” “-ites” become “-ous”

Binary Acids hydro + root element + ic hydro chlor ic acid hydro fluor ic acid hydro brom ic acid hydro iod ic acid HCl HF HBr HI

Oxyacids HClO HClO 2 HClO 3 HClO 4 hypochlorous chlorous chloric perchloric Name is based on the root ion

Oxyacids H 2 SO 4 H 2 SO 3 HNO 3 HNO 2 sulfuric sulfurous nitric nitrous

Oxyacids H 3 PO 4 H 2 CO 3 HBrO 3 HBrO 2 phosphoric carbonic bromic bromous

Binary Molecular Compounds Contain only 2 elements Both elements usually nonmetals Named using either prefix or Stock system

Prefix System Name determined by chemical formula Ending of second element changed to -ide Subscripts in formula determine appropriate prefixes

Prefix System A subscript of 1 usually not given a prefix –Exception: multiple compounds –Second element gets “mon” or “mono” prefix –Most common for oxides of C, N, or H

Rules for Applying Prefixes CO carbonmonoxide PCl 3 phosphorustrichloride N2ON2O dinitrogenmonoxide

Formulas of Binary Molecular Compounds Use the name of the compound to determine its formula Prefixes in the formula tell the subscripts needed for each atom in the formula