6 Formulas Rules for Writing Formulas Metallic Donor is always written first.Nonmetallic Receiver is written second.Write the number of atoms required to balance the formula as subscripts after the element in compound.NaClMgOMgCl2
12 HW: Write the Name of the Compound MgS 7) KBr2) Ba3N2 8) FeO3) NaI 9) SrF24) Li2S 10) CaO5) Na3P 11) Al2O36) KCl 12) Fe2O3
13 Formulae of binary ionic compounds Binary – only two elements presentThe rules –symbol for the cation first, followed by the symbol for the anion.Determine the lowest whole number ratio of ions that will provide a net charge of zeroThe ‘crossover’ method is another way to determine formulae (check page 79)Work through the Sample Problems page 80,81
14 ReviewComplete the revision questions page 81 (13 – 16)
15 Ions of Variable Charge Some transition metals have quite complicated arrangement of electrons and may be able to form more than one ion. Such ions have different charges.This is very significant as ions of the same element with different charges have different physical and chemical properties.Eg – a solution of Cr6+ is orange, whereas a solutions of Cr3+ is yellow.
16 Ions of Variable Charge Iron can form FeO (black) and Fe2O3 (brown), each with different physical and chemical properties. Therefore you must name them differently.They cannot each be called iron oxide.Therefore black FeO containing Fe2+ ions is called iron (II) oxide.The brown Fe2O3 contains Fe3+ ions and is name iron (III) oxide.
17 Ions of Variable Charge Metal ions that form more than one cation include iron (II) and (III), copper (I) and (II), and mercury (I) and (II).Note the roman numeral do not indicate the numbers of ions present in the compound, only the charge of the ion.
18 Ions of Variable Charge Work through the Sample Problem page82
19 ReviewComplete the revision questions page 82 (17,18)
20 HW: Write the Correct Formula Magnesium Oxide2) Lithium Bromide3) Calcium Nitride4) Sodium Sulfide5) Copper (I) Sulfide6) Copper (II) Sulfide
21 Practice Exercise #1 Which will donate, Which will receive? How many will be donated/received?Write the Ionic Notation of each.Write the formula for each of the following.Lithium OxidePotassium ChlorideSodium NitrideCalcium ChlorideMagnesium SulfideBarium NitrideAluminum FluorideAluminum OxideAluminum Nitride
22 Polyatomic ionsA polyatomic ion is a group of tightly bound atoms that behaves as a single unit and carries an overall charge. It may be a positively or negatively charged ion.The carbonate ion is composed of one carbon atom and three oxygen atoms.The whole group of four atoms carries a negative two charge.
23 Polyatomic Ions Compound Ions A group of COVALENTLY bonded atoms that have a net charge (anion or cation)Most, but not all are Anions.
28 Practice Exercise #3 Give the Ionic Notation and Formula for each. Potassium SulfateMagnesium SulfiteAluminum NitrateSodium NitriteLithium CarbonateSodium CyanideBarium HydroxideAmmonium ChlorideAmmonium HydroxideDraw/Diagram Magnesium Sulfite
29 Practice Exercise #4Write out the Ionic Notation, Formula and Names of the following ionic compounds:Li and F - Na and CO3-2Na and S - Li and OH-1K and Br - NH4+1 and ClRb and O - Ca and SO4-2Ca and Cl - NH4+1 and OH-1Mg and SO Na and CN-1Al and NO NH4+1 and SO4-2
30 Polyatomic ionsWork through the Sample Problem pages 84, 85
31 ReviewComplete the revision questions page 85 (19 – 21)
32 Hydrated ionic compounds A number of ionic compounds, called hydrates, produce water when they decompose upon heating. When the formula of a hydrated compound is written, the number of water molecules is also included.Eg. – the formula for iron(II) sulphate octahydrate is written as FeSO4 . 8H2O.This formula indicates that eight molecules of water are bonded within the ionic crystal for every one formula unit of FeSO4Work through the Sample Problem page 86
33 Review Complete the revision question page 86 (22) Complete the multiple choice questions pages 86, 87Complete review questions 1, 3, 5, 6, 8, 10, 11, 13Complete the Exam Practice QuestionsTry this ionic compound construction kit - Ionic Compounds