Chapter 6 Compounds and Their Bonds Naming and Writing Ionic Formulas

Naming Ionic Compounds with Two Elements To name a compound that contains two elements, identify the cation and anion. name the cation first followed by the name of the anion.

Charges of Representative Elements Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

Names of Some Common Ions Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

Learning Check Complete the names of the following ions. Ba2+ Al3+ K+ _________ __________ _________ N3 O2 F _________ __________ _________ P3 S2 Cl

http://youtu.be/mrhE4lyqJ0A Part 2 of writing compounds

Solution Ba2+ Al3+ K+ barium aluminum potassium N3 O2 F nitride oxide fluoride P3 S2 Cl phosphide sulfide chloride

Examples of Ionic Compounds with Two Elements Formula Ions Name cation anion NaCl Na+ Cl- sodium chloride K2S K+ S2- potassium sulfide MgO Mg2+ O2- magnesium oxide CaI2 Ca2+ I- calcium iodide Al2O3 Al3+ O2- aluminum oxide

Learning Check Write the names of the following compounds. 1) CaO ___________ 2) KBr ___________ 3) Al2O3 ___________ 4) MgCl2 ___________

Solution Write the names of the following compounds: 1) CaO calcium oxide 2) KBr potassium bromide 3) Al2O3 aluminum oxide 4) MgCl2 magnesium chloride

Learning Check Write the formulas and names for compounds of the following ions: Br− S2− N3− Na+ Al3+

Solution Na+ Al3+ NaBr sodium bromide Na2S sodium sulfide Na3N Br− S2− N3− Na+ Al3+ NaBr sodium bromide Na2S sodium sulfide Na3N sodium nitride AlBr3 aluminum bromide Al2S3 aluminum sulfide AlN aluminum nitride

Transition Metals form Positive Ions Most transition metals and Group 4(14) metals form 2 or more positive ions. Zn2+, Ag+, and Cd2+ form only one ion.

Metals that form more than One Cation The name of metals with two or more positive ions (cations) use a Roman numeral to identify ionic charge. Lead Pb2+ lead(II) Pb4+ lead(IV) Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

Naming Ionic Compounds with Variable Charge Metals Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

Naming Variable Charge Metals Transition metals with two different ions use a Roman numeral after the name of the metal to indicate ionic charge.

Naming FeCl2 To name FeCl2 1. Determine the charge of the cation using the charge of the anion (Cl-). Fe ion + 2 Cl- = Fe ion + 2- = 0 Fe ion = 2+ 2. Name the cation by the element name and add a Roman numeral in parenthesis to show its charge. Fe2+ = iron(II) 3. Write the anion with an ide ending. FeCl2 = iron(II) chloride

Naming Cr2O3 To name Cr2O3 1. Determine the charge of cation from the anion (O2-). 2 Cr ions + 3 O2- = 0 2 Cr ions + 3(2-) = 0 2 Cr ions - 6 = 0 2 Cr ions = +6 Cr ion = 3+ = Cr3+ 2. Name the cation by the element name and add a Roman numeral in parenthesis to show its charge. Cr3+ = chromium(III) 3. Write the anion with an ide ending. chromium(III) oxide = Cr2O3

Learning Check Select the correct name for each. A. Fe2S3 1) iron sulfide 2) iron(II) sulfide 3) iron(III) sulfide B. CuO 1) copper oxide 2) copper(I) oxide 3) copper(II) oxide

Solution Select the correct name for each. A. Fe2S3 3) iron (III) sulfide Fe3+ S2- B. CuO 3) copper (II) oxide Cu2+ O2-

Guide to Writing Formulas from the Name Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

Writing Formulas Write a formula for potassium sulfide. 1. Identify the cation and anion. potassium = K+ sulfide = S2− 2. Balance the charges. K+ S2− K+ 2(1+) + 2(1-) = 0 3. 2 K+ and 1 S2− = K2S

Writing Formulas Write a formula for iron(III) chloride. 1. Identify the cation and anion. iron (III) = Fe3+ (III = charge of 3+) chloride = Cl− 2. Balance the charges. Fe3+ Cl− Cl− = (3+) + 3(1-) = 0 Cl− 3. 1 Fe3+ and 3 Cl− = FeCl3

Learning Check What is the correct formula for each of the following? A. Copper(I) nitride 1) CuN 2) CuN3 3) Cu3N B. Lead(IV) oxide 1) PbO2 2) PbO 3) Pb2O4

Solution The correct formula is A. Copper (I) nitride 3) Cu3N Need 3Cu+ and N3- B. Lead (IV) oxide 1) PbO2 Need Pb4+ and 2O2-

Naming Cations and Anions Monatomic Ions Ions formed by one element Cations * for Group A elements – just write element’s name ex: calcium ion (Ca2+) = calcium * for Group B elements – write element’s name, then Roman numerals in parentheses to denote charge ex: Fe2+ = Iron (II) and Fe3+ = Iron (III) Anions – drop the end of the element’s name & add “–ide” ending ex: chlorine ion (Cl1-) = chloride Cations – for those with only one charge, just write the element’s name; for transition metals with more than one possible charge, write the element’s name, followed by Roman numerals in parenthesis to denote the charge. Never write a Roman numeral after a monatomic cation that only has one possible charge Anions – drop the end of the element’s name and add an –ide ending

Naming Cations and Anions Polyatomic Ions Ions formed by more than one type of element Atoms of different elements held together by covalent bonds Atoms always stay together and collectively have a single charge Do not always have “-ide” ending ex: NH41- = ammonium ion CO32- = carbonate ion Learn names, formulas, and charges of polyatomic ions! Polyatomic ions are atoms of more than one type of element that stay together by covalent bonds and collectively have a single charge. Certain polyatomic ions are very common. You should be able to write the polyatomic ions listed on your handout with their charges.

Naming Cations and Anions Stop Write the name or symbol w/ charge: Potassium ion Copper (II) ion Chloride ion Oxide ion Ba2+ S2- Au3+ Nitrite ion Hydroxide ion Phosphate ion SO42- CrO42- ClO32- Practice writing names and formulas of ions by writing the answers in your notebook.

Binary Ionic Compounds Compounds composed of 2 different monatomic elements To write binary formulas – write cation first, then anion *criss-cross charges to determine how many of each ion you need *use subscripts to denote number of ions ex: Ca2+ + Cl1- CaCl2 Na1+ + Cl1- NaCl To name binary compounds – write name of cation first, then anion (-ide) ex: CaCl2 = calcium chloride Li2O = lithium oxide Binary ionic compounds – are compounds composed of two different monatomic elements To write formulas for binary ionic compounds, write the symbol for the cation first, followed by the anion. Cross-over the charges by using the absolute value of each ion’s charge as a subscript for the other ion. If there is only one ion needed in a formula, a subscript is not needed (don’t write “1”) To name binary ionic compounds, write the name of the cation first, followed by the name of the anion with the –ide ending

Ternary Ionic Compounds Compounds containing at least one polyatomic ion; at least 3 different elements To write ternary formulas: write cation first, then anion *criss-cross charges to determine how many of each ion you need *use subscripts to denote number of ions *must use parentheses around polyatomic if more than one is needed!!! ex: Na1+ + SO32- Na2SO3 Mg2+ + OH1- Mg(OH)2 [not same as MgOH2] To name ternary compounds: write name of cation, then name of anion (not all end in “-ide”) **be careful with transition metals (more than one charge)** ex: CaCO3 = calcium carbonate PbSO4 = lead (II) sulfate Ag2CrO4 = silver chromate Ternary ionic compounds – compounds containing at least one polyatomic ion; have at least 3 different elements To write the formulas for ternary ionic compounds, use the same rules as for binary compounds Except: use parentheses when more than one polyatomic ion is needed; use criss-cross method like binary To name ternary ionic compounds, use the name rules as for binary compounds except remember that some polyatomic anions do not end in –ide. Be sure to note the exceptions.

Ionic Compounds Stop Write the name or the formula for the following compounds: NaNO3 CaSO4 (NH4)2O CuSO3 Fe(OH)3 NaF Lithium sulfide Iron (III) phosphide Magnesium fluoride Barium nitrate Aluminum hydroxide Potassium phosphate Practice writing names and formulas of ionic compounds by writing the answers in your notebook. Practice making ionic compounds!

Binary Molecular Compounds Two nonmetals joined by covalent bonds Use prefixes for naming 1 = mono- 2 = di- 3 = tri- 4 = tetra- 5 = penta- 6 = hexa- 7 = hepta- 8 = octa- 9 = nona- 10 = deca- Binary Molecular Compounds are compounds made of nonmetals joined by covalent bonds When binary molecular compounds are named, prefixes are used to denote how many atoms of each element are present

Binary Molecular Compounds To name binary molecular compounds: *first element gets a prefix if there is more than one *second element ALWAYS gets prefix, and “-ide” ending ex: N2O3 = dinitrogen trioxide CO = carbon monoxide (not monocarbon) If element begins with vowel and prefix ends in “a” or “o”, then drop last vowel on prefix to form the name ex: Cl2O7 = dichlorine heptoxide (not heptaoxide) To name binary molecular compounds the first element gets a prefix if there is more than one atom of that element the second element ALWAYS gets a prefix and ends in –ide. If the element begins with a vowel and the prefix you add ends in an “a” or an “o”, drop the last vowel on the prefix to form the name

Write the name or formula for the following compounds: Molecular Compounds Stop Write the name or formula for the following compounds: P2O5 N2O NO2 CBr4 CO2 tetraiodine nonoxide sulfur hexafluoride nitrogen trioxide carbon tetrahydride phosphorus trifluoride Now practice writing the correct name or formula for the following molecular compounds in your notebook.