Chapter 6, Sec. 2: Ternary Compounds

Ternary Ionic Compounds l Ternary compounds have atoms of 3 or more elements. l This usually means that either the anion or (less often) the cation is a polyatomic ion. l Sometimes both ions!!

Polyatomic ions l Groups of atoms that stay together and have an overall charge. l Acetate (C 2 H 3 O 2 ) 1- l Nitrate (NO 3 ) 1- l Nitrite (NO 2 ) 1- l Hydroxide (OH) 1- and Cyanide (CN) 1- l Permanganate (MnO 4 ) 1-

Other Polyatomic ions l Sulfate SO 4 2- l Sulfite SO 3 2- l Carbonate CO 3 2- l Chromate CrO 4 2- l Dichromate Cr 2 O 7 2- l Phosphate PO 4 3- l Phosphite PO 3 3- l Ammonium NH 4 1+

Burns Chapter 6 5 Polyatomic Ions Polyatomic ions are groups of covalently bonded atoms that act as a discrete unit and have a net positive or negative charge. TREAT THEM AS A UNIT. Ions with -1 charge perbromate BrO 4 -1 bromate BrO 3 -1 bromite BrO 2 -1 hypobromite BrO -1 perchlorate ClO 4 -1 chlorate ClO 3 -1 chlorite ClO 2 -1 hypochlorite ClO -1 periodate IO 4 -1 iodate IO 3 -1 iodite IO 2 -1 hypoiodite IO -1 nitrateNO 3 -1 nitriteNO 2 -1 hydroxideOH -1 cyanideCN -1 acetateC 2 H 3 O 2 -1 PermanganateMnO 4 -1 bicarbonateHCO 3 -1 Ions with a -2 Charge carbonateCO 3 -2 sulfateSO 4 -2 sulfite SO 3 -2 chromate CrO 4 -2 dichromate Cr 2 O 7 -2 oxalate C 2 O 4 -2 Ions with a -3 Charge phosphate PO 4 -3 phosphite PO 3 -3 arsenate AsO 4 -3 Ions with +1 charge ammonium ion NH 4 +1

Adding Polyatomic ions Ammonium Hydroxide Nitrate Nitrite Sulfate Sulfite Phosphate Polyatomic ions –ions made from groups of atoms that are covalently bonded together and function as a unit. NH 4 + OH - NO 3 - NO 2 - SO 4 2- SO 3 2- PO 4 3-

Polyatomic Suffix Rules l There are two “rules” that can be used when learning the names of polyatomic ions: 1. The prefix “bi-” means a hydrogen is added to the ion’s formula and its charge is increased by 1 ( as a result of the +1 charge carried by the hydrogen ion.) An alternative to the bi- prefix is to use the word hydrogen in its place: the anion derived from H + + (CO 3 ) 2-  (HCO 3 ) - can be called either bicarbonate or hydrogen carbonate.

Polyatomic Suffix Rules

2. If you go one step farther, all of the oxygens are removed and you are back to the monatomic chloride ion: Cl - - just one Cl (Oxygens all went “bye-bye”.)

Polyatomic Suffix Rules 2. This table shows how Rule 2 applies to the chlorate family of ions: l Think of the chlorate ion as being the “base” name. Adding one more oxygen to “-ate” gives you perchlorate.

Polyatomic Suffix Rules 2. In all of these cases, the ion charge is not affected. All of the chlorine/oxygen polyatomic ions have a 1- charge (see formula line). l Changing chlorate to chlorite reduces the # of oxygens from 3 to 2. Adding the prefix “hypo-” to hypochlorite” reduces oxygens from two to one.

Polyatomic Suffix Rules l The “-ite” ion has one less oxygen than the “-ate”, but different “-ate” bases have different numbers of oxygen atoms: Base Ion Name NitrateSulfatePhosphate Base ion Formula (NO 3 ) - (SO 4 ) 2- (PO 4 ) 3- “-ite” ion Name NitriteSulfitePhosphite “-ite” ion Formula (NO 2 ) - (SO 3 ) 2- (PO 3 ) 3-

Polyatomic Suffix Rules l These rules will not work with all polyatomic ion families, but do work with the most common ones: sulfate, phosphate, nitrate and chlorate. l Note: the “per-” prefix is most commonly used with halogen ( VII A ) polyatomics: perchlorate, perbromate, etc. Peroxide ( O 2 ) - & permanganate (MnO 4 ) - ions also exist, but we will not be looking at their “families”.

Naming Ternary Ionic Compounds: l will have polyatomic ions l (and at least three elements) l Name these ions: l NaNO 3 l CaSO 4 l K 2 SO 3 l (NH 4 ) 2 O Sodium nitrate Calcium sulfate Potassium sulfite Ammonium oxide

Writing Ternary Formulas l The charges on the positive cations and negative anions still have to add up to zero. l Balance the charges by adding subscripts. l Put polyatomics in parentheses.

Things to look for l If cations have ( ), the number outside the parentheses is the charge. l Most anions that end in -ide are monoatomic, except: –(OH) - - hydroxide and –(CN) - - cyanide l If an anion ends in -ate or -ite, it is definitely polyatomic.

Criss Crossing with Polyatomic Ions Treat polyatomic ions as a unit. Place the subscript number outside of the parentheses.

Write the formulas for these l Aluminum sulfate l Gallium nitrate l Ammonium chloride l Ammonium sulfide l Barium nitrate Al 2 (SO 4 ) 3 Ga(NO 3 ) 3 (NH 4 )Cl (NH 4 ) 2 Cl Ba(NO 3 ) 2

Chapter 6, Sec. 2: Transition Metals

What about the others? l Transition metals are the “B” groups in the middle of the periodic table. l Many transition metals have more than one common ionic charge.

A 2A 3A 5A6A7A 0 4A Transition Metals can have more than one valence.

Naming Transition Metals l Two methods if more than one charge is possible: –1. Stock system – uses Roman numerals in parentheses to indicate the numerical value –2. Classical method – uses root word with suffixes (-ous, -ic)

Naming Transition Metals l Stock System Examples: l Cu 2+ - Copper (II) ion l Cu + - Copper (I) ion l Fe 3+ - Iron (III) ion l Fe 2+ - Iron (II) ion l Pb 4+ - Lead (IV) ion l Pb 2+ - Lead (II) ion

Naming Transition Metals l Classical Naming Examples: l Cu 2+ - Cupric ion Higher Valence l Cu + - Cuprous ion Lower Valence l Fe 3+ - Ferric ion Higher Valence l Fe 2+ - Ferrous ion Lower Valence l Pb 4+ - Plumbic ion Higher Valence l Pb 2+ - Plumbous ion Lower Valence

Naming Transition Metals l Classical Naming Examples: l Cu 2+ - Cupric ion l Cu + - Cuprous ion l Fe 3+ - Ferric ion l Fe 2+ - Ferrous ion l Pb 4+ - Plumbic ion l Pb 2+ - Plumbous ion Classical method does not give the true value of the charge.

Exceptions: l Some of the transition metals have only one ionic charge: l We do not use Roman numerals for these: –Silver is always 1+ (Ag + ) –Cadmium and Zinc are always 2+ (Cd 2+ and Zn 2+ )

Naming Transition Metals l I have shown you both the Stock and Classical Naming Methods. l You will only have to know how to use the Stock System for naming Transition Metal Compounds for this class.

Naming Binary Ionic Compounds l …is a little trickier with transition metals. l Need to figure out their charges. l The compound must be neutral. (same number of + and – charges). l Use the negative ion to determine the charge on the positive ion:

Naming Binary Ionic Compounds l Write the name of CuO: l Need to calculate the charge of Cu l Charge on O is always 2- l Formula tells us there is one Cu and one O l So charge on Copper (Cu) must be 2+ l Use Roman numerals to indicate charge: l Copper (II) oxide

Naming Binary Ionic Compounds l Write the name of CoCl 3 : l Need to calculate the charge of Co l Charge on Cl is always 1- l Formula tells us there is 1 Co & 3 Cl s l Cl is 1-, there are 3 of them = 3- l So charge on Cobalt (Co) must be 3+ l Use Roman numerals to indicate charge: l Cobalt (III) chloride

Naming Binary Ionic Compounds l Write the name of Cu 2 S. l Since S is 2-, the Cu 2 must be 2+, so each Cu is 1+. l Copper (I) sulfide

Naming Binary Ionic Compounds l Write the name of Fe 2 O 3 l Each O is 2- 3 x (- 2) = - 6 l 2 Fe must = 6+, so each Fe is 3+ l Iron (III) oxide

Naming Transition Metal Compounds l Write the names of the following: l CuCl 2 l Fe 2 (SO 4 ) 3 l Cr(NO 3 ) 3 l Cu(SO 4 ) Copper (II) chloride Iron (III) sulfate Chromium (III) nitrate Copper (II) sulfate

Naming Transition Metal Compounds l Write the names of the following l Co 3 (PO 4 ) 2 l PbO l PbO 2 Cobalt (II) phosphate Lead (II) oxide Lead (IV) oxide

Helpful to remember In an ionic compound, the net ionic charge is zero (criss-cross method). 2. An -ide ending generally indicates a binary compound. 3. An -ite or -ate ending means there is a polyatomic ion that has oxygen.

Nomenclature PO 4 3- phosphate ion C 2 H 3 O 2 - acetate ion HC 2 H 3 O 2 Acetic Acid Chemistry 1: Chapter 9 Chemistry 1 Honors: Chapter 4 ICP: Chapter 20 SAVE PAPER AND INK!!! When you print out the notes on PowerPoint, print "Handouts" instead of "Slides" in the print setup. Also, turn off the backgrounds (Tools>Options>Print>UNcheck "Background Printing")!

CATION + ANION ---> COMPOUND COMPOUND CATION + ANION ---> COMPOUND COMPOUND A neutral compound requires equal number of + equal number of + and - charges. A neutral compound requires equal number of + equal number of + and - charges. COMPOUNDS FORMED FROM IONS Na + + Cl - --> NaCl

IONIC COMPOUNDS NH 4 + Cl - ammonium chloride, NH 4 Cl

Some Ionic Compounds Mg 2+ + N > Mg 3 N 2 magnesium nitride Sn 4+ + O > SnO 2 Tin (IV) oxide calcium fluoride Ca F - ---> CaF 2

NO 3 - nitrate ion NO 2 - nitrite ion Polyatomic Ions

Naming Molecular Compounds CH 4 methane BCl 3 boron trichloride CO 2 Carbon dioxide All are formed from two or more nonmetals. Ionic compounds generally involve a metal and nonmetal (NaCl)