Chapter 9 Chemical Names and Formulas Hingham High School Mr. Dan Clune

Section 9.1 Naming Ions

Ions consisting of a single atom with a positive or negative charge. Monatomic Ions

Naming ions Two methods if more than one charge is possible: Two methods if more than one charge is possible: 1. Stock system – uses roman numerals in parenthesis to indicate the numerical value. 2. Classical method – uses root word with suffixes (-ous, -ic)  Does not give true value.

Naming ions We will use the Stock system. We will use the Stock system. Cation- if the charge is always the same (Group A) just write the name of the metal. Cation- if the charge is always the same (Group A) just write the name of the metal.

Naming Cations Group 1A has a 1+ charge Group 1A has a 1+ charge K 1+ → Potassium Ion Group 2A has a 2+ charge Group 2A has a 2+ charge Mg 2+ → Magnesium Ion Group 3A has a 3+ charge Group 3A has a 3+ charge Al 2+ → Aluminum Ion

Naming ions Transition metals can have more than one type of charge. Transition metals can have more than one type of charge. –Indicate the charge with roman numerals in parenthesis. (Table 9-2, p.255)

Naming Cations Transition Elements Transition Elements can have more than one Oxidation Number. Iron can have 2+ or 3+ charges Fe 2+ → Iron(II) Ion Fe 3+ → Iron(III) Ion

Name these Na 1+ Na 1+ Ca 2+ Ca 2+ Al 3+ Al 3+ Cu + Cu + Cu 2+ Cu 2+ Pb 2+ Pb 2+ Li 1+ Li 1+ Sodium Ion Sodium Ion Calcium Ion Calcium Ion Aluminum Ion Aluminum Ion Copper(I) Ion Copper(I) Ion Copper(II) Ion Copper(II) Ion Lead(II) Ion Lead(II) Ion Lithium Ion Lithium Ion

Naming Anions Anions are always the same charge Anions are always the same charge Change the element ending to – ide Change the element ending to – ide F 1- Fluorine F 1- Fluorine

Naming Anions Anions are always the same charge Anions are always the same charge Change the element ending to – ide Change the element ending to – ide F 1- Fluorin F 1- Fluorin

Naming Anions Anions are always the same charge Anions are always the same charge Change the element ending to – ide Change the element ending to – ide F 1- Fluori F 1- Fluori

Naming Anions Anions are always the same charge Anions are always the same charge Change the element ending to – ide Change the element ending to – ide F 1- Fluor F 1- Fluor

Naming Anions Anions are always the same charge Anions are always the same charge Change the element ending to – ide Change the element ending to – ide F 1- Fluori F 1- Fluori

Naming Anions Anions are always the same charge Anions are always the same charge Change the element ending to – ide Change the element ending to – ide F 1- Fluorid F 1- Fluorid

Naming Anions Anions are always the same charge Anions are always the same charge Change the element ending to – ide Change the element ending to – ide F 1- Fluoride F 1- Fluoride

Name these Cl 1- Cl 1- N 3- N 3- Br 1- Br 1- O 2- O 2- Ga 3+ Ga 3+ Chloride Chloride Nitride Nitride Bromide Bromide Oxide Oxide Gallium Gallium

Write these Sulfide ion Sulfide ion Iodide ion Iodide ion Phosphide ion Phosphide ion Strontium ion Strontium ion S 2- S 2- I 1- I 1- P 3- P 3- St 2+ St 2+

Halide Ions The ions that are produced when atoms of chlorine and other halogens gain electrons. Cl Cl - +e-+e- F F - +e-+e- Br Br - +e-+e-

Exceptions: Some of the Transition Metals have only one ionic charge: Some of the Transition Metals have only one ionic charge: Do not use roman numerals for these: Do not use roman numerals for these: –Silver is always 1+ (Ag 1+ ) –Cadmium and Zinc are always 2+ (Cd 2+ and Zn 2+ )

Polyatomic Ions Groups of atoms that stay together and have a charge. Groups of atoms that stay together and have a charge. Most Polyatomic Ions end in: Most Polyatomic Ions end in:  “ite”  “ate”

[] 1- Nitrite ONO

ON [] 1- Nitrate O O

Polyatomic ions Acetate C 2 H 3 O 2 1- Acetate C 2 H 3 O 2 1- Nitrate NO 3 1- Nitrate NO 3 1- Nitrite NO 2 1- Nitrite NO 2 1- Hydroxide OH 1- Hydroxide OH 1- Cyanide CN 1- Cyanide CN 1- Permanganate MnO 4 1- Permanganate MnO 4 1-

Polyatomic ions Sulfate SO 4 2- Sulfate SO 4 2- Sulfite SO 3 2- Sulfite SO 3 2- Carbonate CO 3 2- Carbonate CO 3 2- Chromate CrO 4 2- Chromate CrO 4 2-

Polyatomic ions Dichromate Cr 2 O 7 2- Dichromate Cr 2 O 7 2- Phosphate PO 4 3- Phosphate PO 4 3- Phosphite PO 3 3- Phosphite PO 3 3- Ammonium NH 4 1+ Ammonium NH 4 1+

Adding Hydrogen to a Polyatomic Ion H + + C → HCO 3 - H + + C → HCO 3 - Hydrogen + Carbonate → Hydrogen Carbonate Carbonate H + + P → HPO 4 2- H + + P → HPO 4 2- Hydrogen + Phosphate → Hydrogen Phosphate Phosphate

H + + HPO 4 2- → H 2 PO 4 - H + + HPO 4 2- → H 2 PO 4 - Hydrogen + Hydrogen → Dihydrogen Phosphate Phosphate Phosphate Phosphate

Common Anions F - FluorideO 2- OxideN 3- Nitride Cl - ChlorideS 2- SulfideP 3- Phosphide Br - BromideS Sulfate I - IodideC Carbonate P Phosphate

1- 0H - Hydroxide Cl0 - Hypochlorite N0 3 - Nitrate HC0 3 - Bicarbonate C 2 H Acetate

Homework Section 9-1 Review Practice Problems Due: 12/13/05

Section 9-2 Naming and Writing Formulasfor Ionic Compounds

Naming Binary Ionic Compounds Binary Compounds - 2 elements. Binary Compounds - 2 elements. Ionic - a cation and an anion. Ionic - a cation and an anion. To write the names, just name the two ions. To write the names, just name the two ions.

Naming Binary Ionic Compounds Easy with Representative elements (which are Group A elements) Easy with Representative elements (which are Group A elements) NaCl = Na 1+ Cl 1- = NaCl = Na 1+ Cl 1- = Sodium Chloride Sodium Chloride MgBr 2 = Mg 2+ Br 1- = Magnesium Bromide MgBr 2 = Mg 2+ Br 1- = Magnesium Bromide

Naming Binary Ionic Compounds The problem comes with the transition metals. The problem comes with the transition metals. Need to figure out their charges. Need to figure out their charges. The compound must be neutral. The compound must be neutral. same number of + and – charges. same number of + and – charges. Use the anion to determine the charge on the positive ion. Use the anion to determine the charge on the positive ion.

Naming Binary Ionic Compounds Write the name of CuO Write the name of CuO Need the charge of Cu Need the charge of Cu Cu ? O 2- Cu ? O 2- copper must be 2+ copper must be 2+ Copper(II) Oxide Copper(II) Oxide

Naming Binary Ionic Compounds Name CoCl 3 Name CoCl 3 CoCl 3 Cl is 1- and there are three of them = 3- Cl is 1- and there are three of them = 3- Co must be 3+ Co must be 3+ Cobalt (III) Chloride Cobalt (III) Chloride Reverse Criss-Cross Reverse Criss-Cross

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

Naming Binary Ionic Compounds Fe 2 O 3 Fe 2 O 3 Each O is 2- 3 x -2 = -6 Each O is 2- 3 x -2 = -6 2 Fe must = 6+, so each is Fe must = 6+, so each is 3+. Iron(III) Oxide Iron(III) Oxide

Naming Binary Ionic Compounds Write the names of the following KCl KCl Na 3 N Na 3 N CrN CrN Sc 3 P 2 Sc 3 P 2 Potassium Chloride Sodium Nitride Chromium(III) Nitride Scandium(II) Phosphide

Naming Binary Ionic Compounds Write the names of the following PbO PbO PbO 2 PbO 2 Na 2 Se Na 2 Se Lead(II) Oxide Lead(IV) Oxide Sodium Selenide

Ternary Ionic Compounds Consist of polyatomic ions Consist of polyatomic ions At least three elements At least three elements Name the ions Name the ions NaNO 3 NaNO 3 CaSO 4 CaSO 4 (NH 4 ) 2 C 2 O 4 (NH 4 ) 2 C 2 O 4 Sodium Nitrate Calcium Sulfate Ammonium Oxalate

Ternary Ionic Compounds Fe(OH) 3 Fe(OH) 3 NiPO 4 NiPO 4 CuSO 3 CuSO 3 Iron(III) Hydroxide Nickel(III) Phosphate Copper(II) Sulfite

Writing Formulas The charges have to add up to zero. The charges have to add up to zero. Get charges on pieces. Get charges on pieces. Cations from name on table. Cations from name on table. Anions from table or polyatomic. Anions from table or polyatomic. Balance the charges by adding subscripts. Balance the charges by adding subscripts. Put polyatomics in parenthesis. Put polyatomics in parenthesis.

Writing Formulas Write the formula for calcium chloride. Write the formula for calcium chloride. Calcium is Ca 2+ Calcium is Ca 2+ Chloride is Cl 1- Chloride is Cl 1- Ca 2+ Cl 1- would have a 1+ charge. Ca 2+ Cl 1- would have a 1+ charge. Need another Cl 1- Need another Cl 1- Ca 2+ Cl 2 1- (use criss-cross method ) Ca 2+ Cl 2 1- (use criss-cross method )

Criss Cross Method Calcium Chloride Cl Ca Cl

Criss Cross Method Copper(I) Nitride N Cu Cu 3N + 3-

Criss Cross Method Calcium Phosphate PO 4 Ca Ca PO 4 ( ) 2

Write the formulas for these lithium sulfide lithium sulfide tin(II) oxide tin(II) oxide tin(IV) oxide tin(IV) oxide magnesium fluoride magnesium fluoride Li 2 S Li 2 S SnO SnO Sn 2 O Sn 2 O MgF 2 MgF 2

Write the formulas for these copper(II) sulfate copper(II) sulfate iron(III) phosphide iron(III) phosphide gallium nitrate gallium nitrate iron(III) sulfide iron(III) sulfide CuSO 4 CuSO 4 FeP FeP Ga(NO 3 ) 3 Ga(NO 3 ) 3 Fe 2 S 3 Fe 2 S 3

Write the formulas for these Ammonium chloride Ammonium chloride ammonium sulfide ammonium sulfide barium nitrate barium nitrate NH 4 Cl NH 4 Cl (NH 4 ) 2 S (NH 4 ) 2 S Ba(NO 3 ) 2 Ba(NO 3 ) 2

Things to look for If cations have ( ), the number in ( ) is their charge. If cations have ( ), the number in ( ) is their charge. If anions end in -ide they are probably off the periodic table (Monoatomic) If anions end in -ide they are probably off the periodic table (Monoatomic) If anion ends in -ate or -ite it is polyatomic If anion ends in -ate or -ite it is polyatomic

Homework Section 9-2 Review Practice Problems Due: 12/14/05

Molecules and Molecular Compounds Molecule - smallest electrically neutral unit, still has properties of the substance Molecule - smallest electrically neutral unit, still has properties of the substance Made from only nonmetals Made from only nonmetals Can be from one element- O 2 Can be from one element- O 2 Can make a compound- CO 2 Can make a compound- CO 2

Systematic Naming There are too many compounds to remember the names of them all. There are too many compounds to remember the names of them all. Compound is made of two or more elements. Compound is made of two or more elements. Name should tell us how many and what type of atoms. Name should tell us how many and what type of atoms.

Molecular are easier! Ionic compounds use charges to determine how many of each. Ionic compounds use charges to determine how many of each. –Have to figure out charges. –Have to figure out numbers. Molecular name tells you the number of atoms. Molecular name tells you the number of atoms. Uses prefixes to tell you the number of atoms. Uses prefixes to tell you the number of atoms.

Prefixes (Table 9.4, p.269) 1 = mono- 1 = mono- 2 = di- 2 = di- 3 = tri- 3 = tri- 4 = tetra- 4 = tetra- 5 = penta- 5 = penta- 6 = hexa- 6 = hexa- 7 = hepta- 7 = hepta- 8 = octa- 8 = octa- 9 = nona- 9 = nona- 10 = deca- 10 = deca-

Prefixes To write the name, write two words: PrefixnamePrefixname-ide One exception is we don’t write mono- if there is only one of the first element. One exception is we don’t write mono- if there is only one of the first element. No double vowels. (oa oo …) Exceptions!!! No double vowels. (oa oo …) Exceptions!!!

Name These N2ON2ON2ON2O NO 2 dinitrogen monoxide nitrogen dioxide

Name These Cl 2 O 7 CBr 4 dichlorine heptoxide carbon tetrabromide carbon tetrabromide

Name These CO 2 BaCl 2 carbon dioxide barium dichloride

Write formulas for these diphosphorus pentoxide diphosphorus pentoxide tetraiodine monoxide tetraiodine monoxide sulfur hexafluoride sulfur hexafluoride nitrogen trioxide nitrogen trioxide carbon tetrahydride carbon tetrahydride phosphorus trifluoride phosphorus trifluoride aluminum chloride aluminum chloride P 2 O 5 P 2 O 5 I 4 O I 4 O SF 6 SF 6 NO 3 NO 3 CH 4 CH 4 PF 3 PF 3 AlCl 3 AlCl 3

Homework Section 9-3 Review Practice Problems Due: 12/15/05

Acids Writing Names andFormulas

Acids Compounds that give off hydrogen ions when dissolved in water. Compounds that give off hydrogen ions when dissolved in water. Must have H in them. Must have H in them. Will always be some H next to an anion. Will always be some H next to an anion. The anion determines the name. The anion determines the name.

Naming acids If the anion attached to hydrogen ends in -ide, put the prefix hydro- and change -ide to -ic acid.

Naming acids HCl - hydrogen ion and chloride ion – Hydrogen Chloride HCl - hydrogen ion and chloride ion – Hydrogen Chloride Dissolve in Water Dissolve in Water Hydrogen Chloride ichydroacidchlor

Naming acids H 2 S - hydrogen ion and sulfide ion H 2 S - hydrogen ion and sulfide ion Dissolve in Water Dissolve in Water Hydrogen Sulfide ichydroacidsulf

Naming Acids If the anion has oxygen in it, then it ends in -ate or –ite. If the anion has oxygen in it, then it ends in -ate or –ite. Change the suffix -ate to -ic acid (use no prefix) Change the suffix -ate to -ic acid (use no prefix) HNO 3 dissolved in water. Hydrogen nitrate Nitric acid

Naming Acids Change the suffix -ite to - ous acid Change the suffix -ite to - ous acid HNO 2 dissolved in water Hydrogen nitrite Nitrous acid

Name these HF HF H 3 P H 3 P H 2 SO 4 H 2 SO 4 H 2 SO 3 H 2 SO 3 H 2 CrO 4 H 2 CrO 4 Hydrofluoric Acid Hydrophosphic Acid Sulfuric Acid Sulfurous Acid Chromic Acid

Writing Acid Formulas Hydrogen will always be first Hydrogen will always be first Name will tell you the anion Name will tell you the anion Make the charges cancel out. Make the charges cancel out. Starts with hydro?- no oxygen, - ide Starts with hydro?- no oxygen, - ide No hydro?, -ate comes from -ic, - ite comes from -ous No hydro?, -ate comes from -ic, - ite comes from -ous

Example Hydronitric Acid Hydrogen Nitride N 3- H+H+H+H+ H3NH3NH3NH3N

Example Oxalic Acid Hydrogen Oxalate C 2 O 4 2- H+H+H+H+ H2C2O4H2C2O4H2C2O4H2C2O4

Write formulas for these hydroiodic acid hydroiodic acid acetic acid acetic acid carbonic acid carbonic acid phosphoric acid phosphoric acid hydrobromic acid hydrobromic acidHI HC 2 H 3 O 2 H 2 CO 3 H 3 PO 4 HBr

Bases Compounds that give off hydroxide ions when dissolved in water. Compounds that give off hydroxide ions when dissolved in water. Must have OH - in them. Must have OH - in them. Will always be some OH next to an cation(+). Will always be some OH next to an cation(+).

Naming Bases Name of Cation plus Hydroxide Name of Cation plus Hydroxide NaOH Sodium Hydroxide

Writing Chemical Formulas for Bases Write the formula for Barium Hydroxide OH + Ba 2- Ba OH ( ) 2

Homework Section 9-4 Review Practice Problems Due: 12/16/05

Section 9-5 The Laws Governing FormulasandNames

Laws of Definite and Multiple Proportions

Laws of Definite Proportions A given chemical compound always contains the same proportion by mass of its constituent elements.

Laws of Definite Proportions H 2 0 – consist of 2 atoms of H and 1 atom of O H – 2 atoms X 1g = 2g O – 1 atoms X 16g = 16g +18g 11% 89%

Laws of Multiple Proportions Whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.

H20H20H20H20 H202H202H202H202 Laws of Multiple Proportions

H20H20H20H20 H202H202H202H202

Practicing Skills 1. An -ide ending generally indicates a binary compound. 2. An -ite or -ate ending means a polyatomic ion that includes oxygen is in the formula.

Practicing Skills 3. Prefixes in a name generally indicate that the compound is molecular. 4. A Roman numeral after the name of a cation shows the ionic charge of the cation.

Practice Naming Compounds

Practice Writing Formulas

Homework Section 9-5 Review Practice Problems Due: 12/20/05 Test: 12/21/05

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 4. Prefixes generally mean molecular; they show the number of each atom

Helpful to remember A Roman numeral after the name of a cation shows the ionic charge of the cation Use the handout sheets provided by your teacher! Use the handout sheets provided by your teacher!