Chapter 9 Chemical Names and Formulas Ionic Compounds

Learning Targets: I can … identify the charge of ions calculate the amounts of electrons being transferred in an ionic bond explain the ratio between cations and anions in an ionic compound

Vocabulary Terms Monatomic ion- a single ion, Ca2+ or Cl1- Binary Compound – made of two different elements bonded together

Death due to accidental inhalation of DHMO, even in small quantities. Why learning chemical nomenclature is important! Death due to accidental inhalation of DHMO, even in small quantities. Prolonged exposure to solid DHMO causes severe tissue damage. Excessive ingestion produces a number of unpleasant though not typically life-threatening side-effects. DHMO is a major component of acid rain. Gaseous DHMO can cause severe burns. Contributes to soil erosion. Leads to corrosion and oxidation of many metals. Contamination of electrical systems often causes short-circuits. Exposure decreases effectiveness of automobile brakes. Found in biopsies of pre-cancerous tumors and lesions. Given to vicious dogs involved in recent deadly attacks. Often associated with killer cyclones in the U.S. Midwest and elsewhere, and in hurricanes including deadly storms in Florida, New Orleans and other areas of the southeastern U.S. Thermal variations in DHMO are a suspected contributor to the El Nino weather effect.

Chemical reactions occur and bonds form if stability can be increased.

Bonding All of the elements on the periodic table will try and achieve a stable arrangement of electrons like the noble gases.

Bonding All of the elements on the periodic table will try and achieve a stable arrangement of electrons like the noble gases. They will do this by undergoing chemical reactions and forming bonds with other elements in order to gain or lose or share electrons

AlCl3 C6H12O NaCl CO2 H2O Chemical Formulas Show the kinds and numbers of atoms present AlCl3 C6H12O NaCl CO2 H2O

Ionic Compounds Ionic bonds form between metals and nonmetals by a transfer of electrons

Ionic Bonding The electron moves from the metal atom to the nonmetal atom Opposite charges hold the ions together ­- Nonmetal + Metal

Ionic compound: A compound that results when a metal reacts with a nonmetal to form ions called cations and anions.

Ion: Atoms that have gained or lost one or more electrons to acquire a net positive or negative electric charge Na+1 11 p+ 10 e-­ Na 11 p+ 11 e­- Lose 1 e-­

Cation name = name of metal atom Cations – Positive ions formed when metal atoms lose electrons Ca+2 Na+1 Al+3 Cation name = name of metal atom

Anions – Negative ions formed when nonmetal atoms gain electrons Cl-1 S­-2 N­-3 Anion names end in -­ide

Properties of Ionic Compounds Metal + nonmetal atoms Crystalline structure – Crystal lattice Ions are strongly bonded to each other

Ionic compounds are called salts (ex/ NaCl) Simplest ratio of ions is called the formula unit The formula unit shows the lowest whole number ratio of the ions.

Na Cl Ionic Bonding The dots around the element symbol are called Lewis Dots and represent the VALENCE electrons for the atom

Na Cl Ionic Bonding Sodium (Na) transfers its ONE valence electron to Chlorine (Cl) and gives Chlorine a full octet

Na+1 Cl -1 ­ Ionic Bonding Result is a positive Na ion and a negative Cl ion that are attracted to each other (opposite charges)

NaCl Formula Unit

Nomenclature of Ionic Compounds metal + nonmetal with “ide” ending

Why do elements gain or lose electrons? (2) 8 1 outer e­ 2 outer e­ 3 4 5 6 7 Various #’s of outer e­

How do we know the charges? Group 1 elements – lose 1e­ = +1 charge Group 2 elements – lose 2e­ = +2 charge Group 13 elements – lose 3e­ = +3 charge Group 14 elements – gain/lose 4­ = +4/-­4 Group 15 elements – gain 3e­ = ­-3 charge Group 16 elements – gain 2e­ = -­2 charge Group 17 elements – gain 1e­ = -­1 charge Group 18 elements do not gain or lose electrons!

Charges on monoatomic ions +4/­-4 +1 Transition metals can have a variety of charges +2 +3 ­-3 ­-2 ­-1

Transition Metal Ions ­Stock System – use roman numerals to denote charge Fe2+ Iron (II) Fe3+ Iron (III) Cu+ Copper (I) Cu2+ Copper (II) Au+ Gold (I) Au3+ Gold (III)

Special exceptions Regular (non-transition) metals with multiple charges Sn2+ Tin (II) Sn4+ Tin (IV) Pb2+ Lead (II) Pb4+ Lead (IV) You MUST write roman numerals for these elements Memory aide- Roman soldiers carry tin(Sn) and lead (Pb) shields.

Special exceptions Transition metals with single charges Silver (Ag +) Zinc (Zn 2+) Do not write roman numerals for these elements

Polyatomic Ions Ions that contain 2 or more nonmetal elements Groups of nonmetal atoms that carry a charge

SO4-2­ sulfate ion

contain oxygen atoms and are named in a special way Some polyatomic ions contain oxygen atoms and are named in a special way ate – 1 more oxygen atom ite – 1 fewer oxygen atom NO3-1­ NO2-1­ nitrate nitrite

Hypochlorite ClO -1­ Chlorite ClO2 -1­ ClO3 -1­ ClO4 -1­ Chlorate The prefix hypo – means under or too little Hypochlorite ClO -1­ Chlorite ClO2 -1­ ClO3 -1­ ClO4 -1­ Chlorate Perchlorate He prefix per means hyper – means above or too much

Some polyatomic ions end in -­ide cyanide hydroxide CN -1­ OH -1­ ­

NH4 1+ Ammonium ion The only + polyatomic ion The only polyatomic cation

Writing Formulas for Binary Ionic Compounds 2 elements only (Type I)

Na Cl Ionic compounds are neutral. Equal #’s of electrons­ have been transferred. Na Cl

Ionic compounds are neutral. Equal #’s of e­ have been transferred. Na Cl

Ionic compounds are neutral. Equal #’s of e­ have been transferred. Na+1 Cl -1­

NaCl Formula Unit Ionic Compounds have zero net charge Na+1 x 1 Cl-1 x 1 +1 -1

Br Al

Br Al

Br -1 Al

-1 Br -1 Al

-1 Br -1 Al

-1 Br -1 Al+3 -1

AlBr3 Br-1 ­x Formula Unit +3 ­-3 3:1 Ratio between Al and Br Creates a neutral compound Formula Unit AlBr3 Br-1 ­x Al3+ x 1 3 +3 ­-3

P Ca

P Ca

P Ca+2

P Ca+2 Ca

P -3­ Ca+2 Ca

P­ P Ca+2 Ca

P­ P Ca+2 Ca+2

Ca Ca+2 Ca+2 P­ P

Ca Ca+2 Ca+2 P­ P

Ca2+ Ca2+ Ca2+ P­

Ca3P2 P3-­ x Formula Unit +6 ­-6 3:2 Ratio between Ca and P Creates a neutral compound Formula Unit Ca3P2 P3-­ x Ca2+ x 3 2 +6 ­-6

AlBr3 Al Br Writing a binary chemical formula 3+ 1- Metal ion is always written first AlBr3

Ca3P2 Ca P Writing a binary chemical formula 2+ ­3- Metal ion is always written first Ca3P2

Potassium and nitrogen Aluminum and Oxygen Strontium and Phosphorous More Practice Magnesium and Sulfur Calcium and Bromine Potassium and nitrogen Aluminum and Oxygen Strontium and Phosphorous

Naming Binary Ionic Compounds Type I Name the metal ion (same as metal atom) Name the nonmetal ion (by changing the ending and adding ­-ide)

For cations (metal ions) simply name the metal as usual: Na+1 Al+3

For anions (nonmetal ions) – change the ending to ­-ide (may need to drop part of element name) • N­-3 • O­-2 • P­-3 ­

Binary ionic naming examples: CaBr2 K3N Sr3P2 ­

calcium chloride barium oxide aluminum sulfide lithium selenide CaCl2 BaO barium oxide aluminum sulfide lithium selenide

Naming Type II Compounds Stock system (Roman Numerals) for Transition metals Determine if 1st element is a transition metal If yes, use roman numerals when naming

Don’t Forget the Exceptions! Silver (Ag) and Zinc (Zn) do not get a roman numeral Lead (Pb) and Tin (Sn) must have roman numerals

Stock System (for transition metals) Copper (II) chloride = Copper (I) chloride = Iron (III) chloride = Iron (II) chloride = Tin (IV) chloride = Tin (II) chloride =

Ternary Compounds: (w/ polyatomic ions) (Type I or II) Formed from a metal cation and a polyatomic anion Contain 3 or more different elements in the formula Use ( ) around polyatomic ions if there is more than 1. Al(NO3)3

Na 1+ OH 1­ Not Na(OH) NaOH Mg 2+ OH 1­ Mg(OH)2 Not MgOH2

Naming Ternary compounds: Name the metal cation Name the polyatomic ion

K +1 NO3-1­ KNO3

K +1 NO3-1­ KNO3 Potassium nitrate

Ca 2+ PO4 3­ Ca3(PO4)2

Ca 2+ PO4 3­ Ca3(PO4)2

NH4 1+ SO3 2-­ (NH4)2SO3

NH4 1+ SO3 2-­ (NH4)2SO3 Ammonium sulfite

Cu2+ SO42-­ CuSO4

Cu2+ SO42-­ CuSO4 Copper (II) sulfate

Fe2+ NO2-1

Reviewing Ionic Formulas In an ionic formula the net charge is zero An –ide ending usually indicates a binary compound (two elements – metal and nonmetal) Exceptions: cyanide, peroxide, hydroxide An –ate or – ite ending indicates a polyatomic ion that has oxygen in the formula ate = more oxygens ­ ite = fewer oxygens

Reviewing Ionic Formulas A roman numeral after the name of a cation shows the ionic charge on the transition metal cation Ions in the same group have similar formulas (due to the same number of valence electrons) ­ ­ Use ( ) around polyatomic ions if there is more than one* * if there is only one, do not use ( ) Ca3(PO4)2

Naming Molecular Compounds (Covalent) Type III Nonmetal + Nonmetal

The Covalent Bond Sharing of electrons

Properties of Molecular or Covalent Compounds Made from 2 or more non­metals Consist of molecules not ions

Molecular Formulas Show the kinds and numbers of atoms present in a molecule of a compound. Molecular Formula = H2O

Structural formula H N H H NH3 Molecular formula

Molecular Formulas Examples CO2 SO3 N2O5

Rules for Naming Molecular compounds The most “metallic” nonmetal element is written first (the one that is furthest left) The most non­metallic of the two nonmetals is written last in the formula NO2 not O2N All molecular compounds end in -­ide

Molecular compounds Ionic compounds use charges to determine the chemical formula The name of the molecular compound indicates the chemical formula. Uses prefixes to tell you the quantity of each element. You need to memorize the prefixes !

Prefixes Memorize! 1 mono­ 2 di­ 3 tri­ 4 tetra­ 5 penta­ 6 hexa­ 7 hepta­ 8 octa­ 9 nona­ 10 deca­ Memorize!

More Molecular Compound Rules If there is only one of the first element do not put mono­ Example: carbon monoxide (not monocarbon monoxide) If the nonmetal starts with a vowel, drop the vowel ending from all prefixes except di and tri monoxide not monooxide tetroxide not tetraoxide

Molecular compounds N2O5

Molecular compounds N2O5 di

Molecular compounds N2O5 dinitrogen

Molecular compounds N2O5 dinitrogen penta

Molecular compounds N2O5 dinitrogen pentaoxide

Molecular compounds N2O5 dinitrogen pentaoxide

Molecular compounds N2O5 dinitrogen pentoxide dinitrogen pentoxide

Molecular compounds Sulfur trioxide

Molecular compounds Sulfur trioxide S

Molecular compounds Sulfur trioxide S

Molecular compounds Sulfur trioxide S O3

Molecular compounds Sulfur trioxide SO3

Molecular compounds CCl4

Molecular compounds CCl4 monocarbon

Molecular compounds CCl4 monocarbon

Molecular compounds CCl4 carbon

Molecular compounds CCl4 tetra carbon

Molecular compounds CCl4 tetrachloride carbon

Molecular compounds CCl4 tetrachloride carbon Carbon tetrachloride

Write molecular formulas for these diphosphorus pentoxide trisulfur hexaflouride nitrogen triiodide

Common Names H2O NH3

Common Names H2O Water NH3 Ammonia

Names and Formulas for Common Acids (memorize these) HCl Hydrochloric Acid HNO3 Nitric Acid H2SO4 Sulfuric Acid H3PO4 Phosphoric Acid