Ionic Compounds

Ionic Compounds Ion: Any atom that has a charge Cation: An ion with a + charge anion: An ion with a - charge

A bond that forms between (+) metals and (-) non metals. Ionic Bonds A bond that forms between (+) metals and (-) non metals. Electrons are transferred and then the opposite charges attract.

Elements want 8 valence electrons Octet Rule Element always move to become more stable. Most elements change their electron configuration to match the configuration of noble gasses. Elements want 8 valence electrons

1+ 2+ 3+ 3- 2- 1-

Rules for Writing Ionic Compounds 1.Charge must always cancel out + and – charges add up to zero. 2. Find the charges from the periodic table or the chart.

Rules for Writing Ionic Compounds 3.If the charges are the same they cancel out and it is a one to one ratio. Ca1O1 Ca2+ , O2-

4.If they are not find the least common mutiple Ca2+ Cl1- = 2 The number that goes in the formula is what you would multiple the charge by to equal the L. C. M. Ca1Cl2

Rules for Writing Ionic Compounds Or… reduce the charges and use the cross rule Sn4+ O2- Ca2+ Cl1- Sn2+ O1- Sn2+ O1- Ca1Cl2 Sn1O2

Learning Check Write the formulas 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

Rules for Naming Ionic Compounds 1. The first element (metal) name does not change. 2. The second elements name ending changes to -ide NaO MgCl2 Al2S3

Rules for Naming Ionic Compounds (except for polyatomic ions, use the name on the chart) SO42- = sulfate Na2SO4 = sodium sulfate

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

Rules for Naming Ionic Compounds 3. If it is a transition metal Roman Numerals must be used. FeCl2 FeCl FeCl3 The Roman numeral tells you the charge of the transition metal

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.

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

Rules for Naming Ionic Compounds 4. There are no prefixes in ionic compounds

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