How are the following words related? ourozlato de oro aurum All are the word for the element “gold” in Portuguese, Croatian, Spanish, and Latin All are the word for the element “gold” in Portuguese, Croatian, Spanish, and Latin

CHAPTER 9 p. 252 CHEMICAL NAMES AND FORMULAS

SECTION 9.1 p. 253 NAMING IONS

Atoms - neutral same # + and e- Ions are atoms, or groups of atoms, with a charge (positive or negative) different # + and e- gain or lose e-’s Monotomic Ions Monotomic Ions – 1 atom w/ + or - charge

A Cation is… l + ion formed by losing e-’s l Metals lose e-’s l Charge written as superscript K 1+ Has lost one electron (no name change for positive ions) Ca 2+ Has lost two electrons An Anion is… - ion gains e-’s Nonmetals can gain e-’s

Ion High School

Predicting Ionic Charges Group 1A: Lose 1 e- to form 1+ ions H 1+ Li 1+ Na 1+ K 1+ Rb 1+

Predicting Ionic Charges Group 2A: Loses 2 e-’s to form 2+ ions Be 2+ Mg 2+ Ca 2+ Sr 2+ Ba 2+

Predicting Ionic Charges Group 3A: Loses 3 Loses 3 e-’s to form 3+ ions B 3+ Al 3+ Ga 3+

Predicting Ionic Charges Group 4A: Do they lose 4 e-’s or gain 4 e-’s? Do they lose 4 e-’s or gain 4 e-’s? Neither! Group 4A elements rarely form ions (they tend to share)

Predicting Ionic Charges Group 5A: Gains 3 Gains 3 e-’s to form 3- ions N 3- P 3- As 3- Nitride Phosphide Arsenide

Predicting Ionic Charges Group 6A: Gains 2 Gains 2 e-’s to form 2- ions O 2- S 2- Se 2- Oxide Sulfide Selenide

Predicting Ionic Charges Group 7A: Gains 1 e- to form Gains 1 e- to form 1- ions F 1- Cl 1- Br 1- Fluoride Chloride Bromide I 1- Iodide

Predicting Ionic Charges Group 8A: Stable noble gases do not form ions! Stable noble gases do not form ions!

Predicting Ionic Charges Group B elements: Many transition elements Many transition elements have more than one possible oxidation state. have more than one possible oxidation state. Iron (II) = Fe 2+ Iron (III) = Fe 3+ Roman numerals show charges

Naming cations 1) Stock system – Roman numerals in () indicates numerical value 2) Classical method – root word w/ suffixes (-ous, -ic) Doesn’t give true value

Naming cations Stock system. Cation - if the charge is always the same (like in the Group A metals) just write the name of the metal. Transition metals can have more than one charge. Indicate their charge as Roman numeral in () after name of cation (Table 9.2, p.255)

Predicting Ionic Charges Some of the post-transition elements also Some of the post-transition elements also have more than one possible oxidation state. have more than one possible oxidation state. Tin (II) = Sn 2+ Lead (II) = Pb 2+ Tin (IV) = Sn 4+ Lead (IV) = Pb 4+

Predicting Ionic Charges Group B elements: Some transition elements Some transition elements have only one possible oxidation state, such as these three: have only one possible oxidation state, such as these three: Zinc = Zn 2+ Silver = Ag 1+ Cadmium = Cd 2+

Exceptions: Some transition metals have only one ionic charge: Do not use Roman numerals for these: Silver always 1+ (Ag 1+ ) Cadmium and Zinc always 2+ (Cd 2+ and Zn 2+ )

Practice by naming these: Na 1+ Ca 2+ Al 3+ Fe 3+ Pb 2+ Li 1+

Write symbols for these: Potassium ion Magnesium ion Copper (II) ion Chromium (VI) ion Barium ion Mercury (II) ion

Naming Anions Change monatomic element ending to – ide F 1- a Fluorine atom becomes Fluoride ion.

Practice by naming these: Cl 1- N 3- Br 1- O 2-

Write symbols for these: Sulfide ion Iodide ion Phosphide ion

Polyatomic ions Groups of atoms that stay together and have overall charge Usually end in –ate or -ite Acetate: C 2 H 3 O 2 1- Nitrate: NO 3 1- Nitrite: NO 2 1- Permanganate: MnO 4 1- Hydroxide: OH 1- and Cyanide: CN 1- ?

Sulfate: SO 4 2- Sulfite: SO 3 2- Carbonate: CO 3 2- Chromate: CrO 4 2- Dichromate: Cr 2 O 7 2- Phosphate: PO 4 3- Phosphite: PO 3 3- Ammonium: NH 4 1+ Know Table 9.3 on page 257 If polyatomic ion begins with H, then combine the word hydrogen with the other polyatomic ion present: H + + CO 3 2- → HCO 3 - hydrogen + carbonate → hydrogen carbonate ion (One of the few positive polyatomic ions)

Section 9.2 – Marble madness Pair up with someone everyone gets a cup The person in each pair whose birthday is closest to today gets to add 4 marbles in their cups The other person keeps an empty cup Listen for further instructions

SECTION 9.2 P. 260 NAMING & WRITING FORMULAS FOR IONIC COMPOUNDS

Example: Barium nitrate (note the 2 word name) 1. Write the formulas for cation and anion, including CHARGES! Ba 2+ NO Do charges balance? 3. Balance charges, if necessary, using subscripts. Use () if more than one polyatomic ion. Use criss-cross method to balance subscripts. Not balanced! ( ) 2 Now balanced. = Ba(NO 3 ) 2

Writing Ionic Compound Formulas Example: Ammonium sulfate (note the 2 word name) NH 4 + SO Do charges balance? Not balanced! ( ) 2 Now balanced. = (NH 4 ) 2 SO 4 3. Balance charges, if necessary, using subscripts. Use () if more than one polyatomic ion. Use criss-cross method to balance subscripts. 1. Write the formulas for cation and anion, including CHARGES!

Writing Ionic Compound Formulas Example: Iron (III) chloride (note the 2 word name) 1. Write the formulas for cation and anion, including CHARGES! Fe 3+ Cl - 2. Do charges balance? 3. Balance charges, if necessary, using subscripts. Use () if more than one polyatomic ion. Use criss-cross method to balance subscripts. Not balanced! 3 Now balanced. = FeCl 3

Writing Ionic Compound Formulas Example: Aluminum sulfide (note the 2 word name) 1. Write the formulas for cation and anion, including CHARGES! Al 3+ S Do charges balance? 3. Balance charges, if necessary, using subscripts. Use () if more than one polyatomic ion. Use criss-cross method to balance subscripts. Not balanced! 23 Now balanced. = Al 2 S 3

Writing Ionic Compound Formulas Example: Zinc hydroxide (note the 2 word name) 1. Write the formulas for cation and anion, including CHARGES! Zn 2+ OH - 2. Do charges balance? 3. Balance charges, if necessary, using subscripts. Use () if more than one polyatomic ion. Use criss-cross method to balance subscripts. Not balanced! ( ) 2 Now balanced. = Zn(OH) 2

Naming Ionic Compounds 1. Name cation first, then anion 2. Monatomic cation = name of element Ca 2+ = calcium ion 3. Monatomic anion = root + -ide Cl  = chloride CaCl 2 = calcium chloride

Naming Ionic Compounds some metals form more than one charge (usually transition metals) use Roman numeral in name: PbCl 2 – use anion to find charge on cation (chloride always 1-) Pb 2+ is lead (II) cation PbCl 2 = lead (II) chloride (Metals with multiple oxidation states)

Things to look for: 1) If cation has ( ), the number in parenthesis is its charge. 2) If anion ends in –ide, likely monoatomic 3) If anion ends in -ate or –ite, it’s polyatomic

Practice by writing formula or name Iron (II) Phosphate Stannous Fluoride Potassium Sulfide Ammonium Chromate MgSO 4 FeCl 3

Section 9.3 p. 268 Naming and Writing Formulas for Molecular Compounds Molecular cmpds… made of nonmetals smallest piece… molecule not bound by opposite charge attraction can’t use charges to figure # of each atom (no charges present)

Molecular v.s. Ionic Compounds Ionic: use charges to determine # of each Molecular: name tells you # of atoms prefix tells exact # of each element

Know these prefixes (Table 9.4 p. 269) PrefixMonoDiTriTetraPentaHexaHeptaOctaNonadeca Value

Formula Elements # atomsprefixes N2ON2O PBr 5 P4S3P4S3 CS 2 IF 7

Using Prefixes to name covalent compounds To write the name, write two words: One exception…..don’t write mono when only one of first element PrefixnamePrefixname-ide

Using Prefixes to name covalent compounds To write the name, write two words: One exception is we don’t write mono if there is only one of the first element. Normally, we do not have double vowels when writing names (oa oo) Prefixname Prefixname -ide

Practice by naming these: NO 2 Cl 2 O 7 CBr 4 CO 2 BaCl 2 (This one will not use prefixes, since it is an ionic compound!) = nitrogen dioxide = dichlorine heptoxide = carbon tetrabromide = carbon dioxide

Write formulas for these: diphosphorus pentoxide tetraiodine nonoxide phosphorus trifluoride carbon tetrahydride sulfur hexafluoride more SF 6SF 6

Section 9.4 p. 271 Naming and Writing Formulas for Acids and Bases Acids are… Cmpds containing 1 or more H atoms & produces H ions (H 1+ ) when dissolved in H 2 O Chem formula starts with H followed by anion anion determines acid name

Rules for Naming acids: Name it as normal cmpd first 1) If anion ends in –ide: 1)Acid name begins w/ prefix hydro- 2)change -ide to -ic acid HCl (aq) - hydrogen ion and chloride ion = hydro chlor ic acid H 2 S (aq) hydrogen ion and sulfide ion = hydro sulfur ic acid

Naming Acids If anion has O, it ends in -ate or -ite 2)change suffix -ate to -ic acid (no prefix) If you “ate” something acidic, you would probobaly say “ic”!If you “ate” something acidic, you would probobaly say “ic”! Example: HNO 3 Hydrogen and nitrate ions = Nitric acid 3)change the suffix -ite to -ous acid (no prefix) Example: HNO 2 Hydrogen and nitrite ions = Nitrous acid

Anion endingExampleAcid nameExample -ideChlor ide, Cl - Hydro-(stem)-ic acid Hydrochloric acid -iteSulf ite, SO3 2- (stem)-ous acidSulfurous acid -ateNitrate, NO3 - (stem)-ic acidNitric acid

Naming Acids Normal ending ____-ide ____-ate ____-ite Acid name is… hydro-___-ic acid _____-ic acid _____-ous acid

Practice by naming these: HF H 3 P H 2 SO 4 HCN H 2 CrO 4

Write formulas for these: hydroiodic acid acetic acid carbonic acid phosphorous acid hydrobromic acid

Names and Formulas for Bases A base is ionic cmpd producing hydroxide ions (OH 1- ) when dissolved in water Bases named same way as other ionic cmpds: Name of cation (which is a metal) followed by name of anion (hydroxide)

Names and Formulas for Bases NaOH - sodium hydroxide Ca(OH) 2 - calcium hydroxide To write the formula: 1) Write symbol for metal cation 2) followed by formula for hydroxide ion (OH 1- ) 3) use criss-cross method to balance charges

Practice by writing the formula for the following: Magnesium hydroxide Iron (III) hydroxide Zinc hydroxide

Practice by naming the following bases: NaOH NH 4 OH Ca(OH) 2 Al(OH) 3

Section 9.5 p. 274 The Laws Governing Formulas and Names Review: Law of Conservation of Mass? Review: Law of Conservation of Mass? Mass neither created or destroyed but is conserved during any chem rxn Mass reactants = mass products Mass cmpd = mass of SUM of elements in cmpd

1. Law of Definite Proportions (mass) - in a sample of a pure cmpd, masses of elements always in same proportions CO 2 (carbon dioxide) CO (carbon monoxide) Law of Definite Proportions

Law of Multiple Proportions (Dalton’s Law) 2. Law of Multiple Proportions- Dalton stated whenever 2 elements form more than one cmpd, the different masses of 1 element that combine with the same mass of the other element are in the ratio of small whole numbersLaw of Multiple Proportions-

Same mass of oxygen - Page 275

Law of definite and multiple proportions Guided Practice Problem 34 p. 275 (p. 90 #34 in workbook)

p. 275 practice problem #34 Lead forms two compounds with oxygen. One compound contains 2.98 g of Pb and g of O. The other contains 9.89 g of Pb and g of O. For a given mass of oxygen, what is the lowest whole number mass ratio of lead in the two compounds?

Step 1. Write the ratio of lead to oxygen for each cmpd. ______g Pb 9.89 g Pb g O ______g O Step 2. Divide the numerator by the denominator in each ratio ______ _______g Pb _________ g O

Step 3. Write a ratio comparing the first compound to the second. _____ g Pb/g O 13.0 g Pb/g O Step 4. Simplify. Note that this ratio has no units (they cancel out) = roughly 1 1 __

The mass ratio of lead per gram of oxygen in the two compounds is:

Summary of Naming and Formula Writing Naming formulas – flowchart - Figure 9.20, page 277 Writing formulas – flowchart - Figure 9.22, page 278

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 is the ionic charge of the cation