Ions Atoms that lose electrons (negative) have more positive charge than negative charge so they are positive ions. Atoms that gain electrons (negative) have more negative charge than positive charge so they are negative ions. When there are only nonmetal atoms present, they all need additional electrons, so they share electrons amongst themselves.

Ionic Compounds Positive and negative ions will bond to each other because of their electrostatic attraction. This attraction is called an ionic bond. Metals and nonmetals always bond together using ionic bonds.

Periodic Table of the Elements Metals Non-Metals

Naming Ionic Compounds Two word name First word- name of first element in formula Second word- name of second element with ending changed to “ide” Ex: NaCl KF Li2O sodium chloride chlorine potassium fluoride fluorine lithium oxide oxygen

Practice: Write the name of the following ionic compounds MgS CaF2 AlBr3 ZnI2 Mg3N2 magnesium sulfide calcium fluoride aluminum bromide zinc iodide magnesium nitride

How do we know if a compound is ionic? Recap How do we know if a compound is ionic? Metal & Non-metal

Writing Formulas for ionic compounds Write formula for sodium chloride. Start with a picture of the ions: Na+ Cl- Note: Amount of charge tells how many hooks Formula: NaCl Cl- Na+ Another example: sodium oxide Na+ and O2- O-2 Na+ Formula: Na2O Na+

Writing Formulas for ionic compounds, cont’d A third example: aluminum sulfide Al3+ and S2- S-2 Al3+ Formula: Al2S3 S-2 Al3+ S-2

Writing Formulas for ionic compounds We can also use a shortcut method for finding the formulas for ionic compounds: Identify the ions and their charges. Rewrite elements. Cross over the charges and rewrite them as subscripts. Put both parts together and write the subscripts in the simplest form. Example: calcium chloride Ca2+ Cl- Ca Cl 2 CaCl2 ANSWER

Practice Problems Determine the formulas of the following ionic compounds: Lithium fluoride Magnesium bromide Calcium selenide Beryllium iodide Scandium sulphide Strontium oxide Potassium phosphide Aluminum oxide LiF MgBr2 CaSe BeI2 Sc2S3 SrO K3P Al2O3

What’s the difference between a charge Question What’s the difference between a charge and a subscript? A charge tells us how many electrons an element has gained or lost to become an ion. A subscript is used in the written formula of a compound to tell us how many molecules of a certain element are used in that compound.

Ionic Compounds with polyatomic ions Ion composed of more than one element Examples: OH- hydroxide ClO3- chlorate SO42- sulfate/sulphate *More polyatomic ions are listed on the ion side of your periodic table. Note: The charge on a polyatomic ion is on all the listed elements together as a whole. When O and H are together they have a charge of -1.

Naming Ionic Compounds with polyatomic ions Two word name First word- name of first element in formula Second word- name of polyatomic ion Ex: NaOH Mg(CN)2 Li2CO3 Another one: NH4Cl sodium hydroxide magnesium cyanide lithium carbonate ammonium chloride

Practice: Write the name of the following ionic compounds. Mg(OH)2 CaC2O4 = CaOOCCOO NH4Br Zn(BrO3)2 Mg3(BO3)2 Magnesium hydroxide Calcium oxalate Ammonium bromide Zinc bromate Magnesium borate

Writing Formulas for ionic compounds (with polyatomic ions) An example: sodium hydroxide Na+ and OH- Formula: NaOH OH- Na+

Writing Formulas for ionic compounds (with polyatomic ions), cont’d Another example: barium sulfite Ba2+ and SO32- Formula: BaSO3 SO3 -2 Ba2+

Writing Formulas for ionic compounds (with polyatomic ions), cont’d Another example: aluminum sulfate Al3+ and SO42- SO4 -2 Al3+ Formula: Al2(SO4)3 SO4 -2 Al3+ SO4 -2

Writing Formulas for ionic compounds (with polyatomic ions), cont’d Another example: calcium nitrate Ca+2 and NO3- NO3- Ca+2 Formula: Ca(NO3)2 NO3-

Writing Formulas for ionic compounds (with polyatomic ions): criss-cross An example: sodium hydroxide Na+ and OH- Na OH Formula: NaOH

Writing Formulas for ionic compounds (with polyatomic ions), cont’d Another example: barium sulfite Ba2+ and SO32- Ba SO3 BaSO3 2 2 Formula: BaSO3

Writing Formulas for ionic compounds (with polyatomic ions), cont’d Another example: aluminum sulfate Al3+ and SO42- Al SO4 3 2 Formula: Al2(SO4)3

Practice Problems Ca(CN)2 Calcium cyanide Be(OH)2 Beryllium hydroxide Li2CO3 (NH4)2CrO4 Calcium cyanide Beryllium hydroxide Lithium carbonate Ammonium chromate

Polyatomic Ions Worksheet

Multivalent Ionic Compounds Some ions can have more than one possible charge. This is indicated on the periodic table of the ions by dividing the box in half. Ex: Note: Roman numerals are used to indicate the charge of the ion. Titanium (IV) Titanium (III) Roman numerals (1-5): I, II, III, IV, V

Naming Multivalent Ionic Compounds Example: Ti2O3 titanium (III) oxide Two word name First word- name of first element in formula with charge indicated by roman numeral Second word- name of second element with “ide” ending

Naming Multivalent Ionic Compounds Example: CoF2 cobalt (II) fluoride Two word name First word- name of first element in formula with charge indicated by roman numeral Second word- name of second element with “ide” ending

Naming Multivalent Ionic Compounds Example: Mn(OH)4 manganese (IV) hydroxide Two word name First word- name of first element in formula with charge indicated by roman numeral Second word- name of second element/polyatomic compound with “ide” ending

Naming Multivalent Ionic Compounds Example: CrS chromium (II) sulfide Two word name First word- name of first element in formula with charge indicated by roman numeral Second word- name of second element/polyatomic compound with “ide” ending

Practice Name the following multivalent ionic compounds: NiCl3 CuBr Fe(CN)3 CoP VF5 VS2 nickel (III) chloride copper (I) bromide iron (III) cyanide cobalt (III) phosphide vanadium (V) fluoride Vanadium (IV) sulfide

Writing Formulas for multivalent ionic compounds Example: copper (II) nitride Cu2+ and N3- Cu N Cu3N2 3 2 Formula: Cu3N2

Writing Formulas for multivalent ionic compounds Example #2: iron (III) hydroxide Fe3+ and OH- Fe OH Fe(OH)3 1 3 Formula: Fe(OH)3

Practice Problems Name the following multivalent ionic compounds: CuF Mn3P2 Cr3N2 PdO Ti2O3 Cr2S3 Ru2S TiHS4 NiCl3 FePO4 V3N5 Cu(NO2)2 CuBr2 Pd(OH)3

Practice Problems iron (III) sulfide Chromium (II) oxide Write the formula for each multivalent ionic compounds: iron (III) sulfide Chromium (II) oxide Copper (II) phosphide Nickel (III) bromide Lead (IV) sulfate Vanadium (V) cyanide