NOMENCLATURE IONIC BONDING Thursday - Day 3 Notes Click the link below to watch the video: VIDEO CLIP ON HOW ATOMS BOND: IONIC COMPOUNDS http://www.nbclearn.com/portal/site/learn/chemistry -now/how-atoms-bond Quick Review _Ions_____ - atoms that have lost or gained one or more electrons. __cation___ – positively charged ion _____anion___ – negatively charged ion The charge on the ion is known as the ___oxidation number____ __Polyatomic ion____ – ion consisting of two or more atoms Practice - write the ion with the charge for the following elements * Li + * Be * Al * Na *F- 2+ 3+ + 2+ * Ca * Si +-4 * H * K + + 2- * O 2- * Fr + * N 3- * Cl - * P *S 3- NOTES #2: Binary Ionic Chemical Names and Formulas Ionic bonds are formed between a metal and a nonmetal OR cation + anion. The bond involves the transfer of electrons from the metal to the nonmetal. The electron is transferred from the cation to the anion so that both atoms have a complete valence shell (usually 8 electrons in valance). The overall charge of ionic compounds must equal zero. Naming Ionic Compounds * First name the cation and then the anion. (metal) (nonmetal) * Change the ending of the anion to –ide. Example: •MgCl2 magnesium chloride •Li2S Lithium sulfide _________________________ Magnesium oxide MgO _________________________ K3P Potassium phosphide ________________________ CsCl ________________________ Ba3N2 Cesium chloride Barium nitride ________________________ Practice DRAWING Lewis Dot Structures for Ionic Compounds • • The overall charge on the compound must equal zero, that is, the number of electrons lost by one atom must equal the number of electrons gained by the other atom. The Lewis Structure (electron dot diagram) of each ion is used to construct the Lewis Structure (electron dot diagram) for the ionic compound. The Lewis Dot structures show the location of the valence electrons after the electrons have been transferred. Examples: Lithium fluoride • Lithium atom loses one electron to form the cation Li+ • Fluorine atom gains one electron to form the anion F• Lithium fluoride compound can be represented as Remember the Octet rule…. DRAWING Lewis Dot Structures for Ionic Compounds Draw the Lewis structure of Lithium oxide. formula for this compound? What would be the chemical Writing Formulas for Binary Ionic Compounds Balance When given two ions, __________________ the charges and make them the subscripts ___________________. Do NOT keep the +/- signs _______________ Reduce subscripts if possible This means we must reduce the subscripts if they have a common denominator. Example: Ca4F8 CaF2 Writing Formulas for Binary Ionic Compounds A. Using Balanced charges Method: B. Using the Crisscross method: **Sum of charges must equal zero. Ex: a. Na+1 + Cl-1 NaCl Example: Li+1 O-2 (+1 + -1 = 0) b. Mg+2 + O-2 MgO * (+2 + -2 = 0) * Don’t write this Mg2O2 because it must be reduced. Now, let’s use the name to write the chemical formula Name Lithium oxide cation anion Li+1 O-2 _______ _______ Li+1 formula Li2O _____________ Lewis Dot Structure Important Facts about Ionic Compounds • We use subscripts to represent the number of each ion. Al2O3 2 Aluminum Ions and 3 Oxide Ions For example 2…Change it from Magnesium sulfide to Magnesium phosphide A. Using Balanced charges Method: Mg2+ Mg2+ Mg2+ 6+ and B. Using the Crisscross method: Mg2+ P3P3=0 6- Name cation Mg ______ Magnesium phosphide Mg 3 2+ anion formula Mg3P2 P _______ ____________ 3- and P3S2 Lewis Dot Structure Homework: Page 9 For added help: watch this video And use your periodic table!!!! Notes 3: Binary Ionic Compounds with Transition Metals (Multivalent cations) Multivalent Cations are found mostly in the group B elements. (the middle of the periodic table) These elements are also known as the Transition metals. Roman Charge Numeral If your cation is a transition metal, then you must specify the charge with a Roman numeral. Example: Iron (III) Sulfide Just like the compounds we looked at yesterday, the sum of charges must equal zero . and we can still use the Criss-cross method when writing the chemical formula. I II III IV V VI VII VIII +1 +2 +3 +4 +5 +6 +7 +8 Writing & Naming Formulas with Roman Numerals Practice Cu+ S2- Cu2S Mn2+ O 2- MnO Sn4+ F- SnF4 Lead II iodide Pb2+ I- Iron III oxide Fe3+ O2- Lead IV oxide Pb4+ Cobalt III phosphide Co3+ P3- Naming Ionic Compounds with Roman Numerals If there is a transition metal (B group element) present in the formula, you will need to include a roman numeral when you name the compound. So, which metals DO NOT require a roman numeral? 3+ 2+ 2+ and Ag+ Al , Zn , Cd Writing Multivalent Compounds HOMEWORK Complete page 11 REMEMBER: How can you determine the charge or roman numeral? You will have to work backwards. And Roman Numeral = Charge of the Metal Polyatomic Ions A polyatomic ion are groups of atoms that behave as one unit. They are treated like single ions in formulas, but use parenthesis when more than one is used in a formula. NEVER change name or look of polyatomic. If you change the subscripts for any part of the polyatomic, then it is no longer that same polyatomic ion. Otherwise….use all the same rules for naming and writing compounds as with any other Binary Ionic compound. EX: NH4+ is not the same as NH+ CO32- is not the same as CO22- or CO2- Polyatomic Ion Practice Formula Al+3 CO3 -2 Al2(CO3)3 Ca+2 NO3 -1 Ca(NO3)2 K+1 ClO3 -1 KClO3 Name Aluminum carbonate Calcium nitrate Potassium chlorate Question: How would potassium chlorite be different? K+1 ClO2 -1 KClO2 Name the following compounds Ba(OH)2 Barium hydroxide CaSO4 Calcium sulfate (NH4)3P Ammonium phosphide Write the formula for the following compounds: cation anion formula Strontium phosphate 2+ Sr ________ _________ ______________ Lithium acetate ________ _________ ______________ Sodium sulfate _________ _________ ______________ Formula Writing for Compounds Tips for Success Before writing any formula, Identify Ionic the type of compound. Metal and a Nonmetal or PAI Molecular Only Nonmetals For all ionic compounds, circle polyatomic ions. Examples iron(III) nitrate I carbon tetrachlorideM sodium oxide I barium hydroxide I dinitrogen trioxide M ammonium carbonate I cobalt(III) nitrite I Fe(NO3)3 CCl4 Na2O Ba(OH)2 N2O3 (NH4)2CO3 Co(NO2)3 Naming Ionic Compounds with Polyatomic Ions When you name a compound with a polyatomic ion, the polyatomic ion keeps its name. It is easy to identify a compound with a polyatomic ion because it will have more than 2 elements (more than 2 capital letters). Tips for Success Before naming ANY compound, Determine the type of compound. If the compound is molecular, remember use prefixes. If the compound is ionic, answer the following questions. Does the metal need a roman numeral? Does the compound have a polyatomic ion? Examples NaHCO3 I sodium hydrogen carbonate I ammonium oxide (NH4)2O FeSO4 I iron(II) sulfate I AgC2H3O2 silver acetate Ni(NO3)2I nickel(II) nitrate ClO M chlorine monoxide I AuClO3 gold(I) chlorate Monday Bell Ringer Which of the following compounds represent trichlorine hexoxide? A. Cl3O6 B. ClO3 C. O3Cl6 Which of the following compounds represent manganese (III) oxide? A. MgO B. Mn2O3 C. Mg2O3 Properties of Acids Corrosive Sour Taste React with Metals to Produce Hydrogen Gas (H+) pH less than 7 Can conduct electricity Contain H+ ions Generally found as (aq) or aqueous Binary Acids Binary acids are made up of HYDROGEN + ANOTHER ELEMENT. Example: HCl (hydrogen + chlorine) Example: H2S (hydrogen + sulfur) Naming Binary Acids: 1. Prefix: hydro- 2. Element Name 3. –ic 4. Last word: “acid” Ie: hydroelementic acid In Class Examples: Naming Binary Acids HCl hydrochloric acid HF hydrofluoric acid HBr hydrobromic acid Ternary Acids These acids contain a POLYATOMIC ION. Also called oxy-acids. Example: H2SO3 = sulfurous acid Naming Ternary Acids 1. Name the polyatomic ion. 2. Change PAI ending in –ate to –ic. Example: sulfate sulfuric phosphate phosphoric 3. Change PAI ending in –ite to –ous. Example: sulfite sulfurous phosphite phosphorous 4. Last word is “acid”. In Class Examples of Naming Ternary Acids: H2 SO4 sulfuric acid H2 CO3 carbonic acid HNO2 nitrous acid H3PO4 phosphoric acid Writing Acid Formulas You do not have notes on this- we will practice in a minute! Always begins with Hydrogen! Hydrogen = H+ You will then follow the same process as you would an IONIC compound! hydrochloric acid = H+ and Cl- = HCl Example: sulfuric acid = H+ and SO42- = H2SO4 Example: Writing Acid Formulas: Tips: 1. Your first element is ALWAYS H+ 2. Identify if it is a BINARY acid or TERNARY acid. - begins with hydro- and ends in –ic? (1 element!) - no hydro- prefix, or ends in –ous? (PAI!) STOP: IN CLASS PRACTICE I’ll make a SMART board notebook, you will probably want to do it on the overhead. Exit Ticket will be the page in the notes titled “In Class Practice for Nomenclature of Acids.” Darla just emailed out a homework that I’ll probably use! Writing Formulas for Acids Remember your patterns. Hydro-ic acid No oxygen X-ic acid -ate polyatomic ion X-ous acid - ite polyatomic ion The positive ion is always H+. The sum of the charges of the ions must add up to zero. Examples hydroselenic acid H2Se phosphoric acid H3PO4 nitrous acid HNO2 sulfurous acid H2SO3 dichromic acid H2Cr2O7 Keys to Success Before naming ANY compound, Identify the type of compound. Molecular? If Ionic? Acid? it is molecular, remember to use your prefixes. If it is ionic, ask yourself. Does the metal need a roman numeral? Does it contain a polyatomic ion? If it is an acid, which pattern does it follow? Mixing It Up! H2CrO4 A Na2SO3 I HF A P5O10 M I Fe(C2H3O2)2 ZnCl2 I H3PO3 A chromic acid sodium sulfite hydrofluoric acid pentaphosphorus decoxide iron(II) acetate zinc chloride phosphorous acid Keys to Success Before writing the formula for ANY compound, Identify the type of compound. Molecular? Ionic? Acid? If it is ionic, does it contain a polyatomic ion? If it is an acid, which pattern does it follow? No Oxygen? -ATE Polyatomic Ion? -ITE Polyatomic Ion? Examples barium phosphate I A -ate bromic acid Ba3(PO4)2 HBrO3 ammonium dichromateI (NH4)2 Cr2O7 iron(III) sulfide I Fe2S3 dichlorine heptachlorideM Cl2O7 hydrosulfuric acid A No O H2S gold(III) chlorate I Au(ClO3)3 PUZZLE PIECE ACTIVITY ON WRITING FORMULAS FOR IONIC COMPOUNDS •Work in pairs to assemble the various compounds. •Let’s try the first one together. •What is the compound formed between Mg and F? Mg2+ Magnesium Metal Mg Metal’s Charge +2 Ffluoride Ffluoride Nonmetal’s Nonmetal Charge F -1 A perfectly assembled compound should be a square or a rectangle. Picture of Puzzle Pieces Formula Name MgF2 magnesium fluoride Sum of Charges 0