IONIC COMPOUNDS

STABILITY Relates to nobility Every element’s dream They’ll do what they can to look like a noble gas…pseudo-noble gas configuration Duet Rule Octet Rule Potential Energy

Bond Energy The energy required to break a bond The energy is absorbed when the bond is broken, thus…released when formed Stronger bonds are more stable Require more energy to break them i.e. ionic bonds Weaker bonds are less stable Require less energy to break them i.e. molecular or covalent bonds

Achieving Stability Ionic bonds made by transferring electrons Metals will do what? Nonmetals will do what? Once electrons are transferred, the atoms are converted to ions. lose electron(s) gain electron(s)

Ions Positively charged ions are called? Negatively charged ions are called? Bond to make an ionic compound or salt cations anions

Salts Made of metals and nonmetals or polyatomic ions Solid Brittle Ordered arrangement called crystal lattice Brittle High melting point Electrical conductors in aqueous and molten phases

More About Ions Written as a symbol with superscript to the right indicating the charge Charge is written as a number followed by a + or – sign Monatomic ions— “one-atomed” ions Polyatomic ions— “many-atomed” ions

Monatomic Ions Use periodic table to determine charges of representative elements Group 1…1+…element name + ion Group 2…2+…element name + ion Group 13…3+…element name + ion Group 14…skip Group 15…3-…ide ending + ion Group 16…2-…ide ending + ion Group 17…1-…ide ending + ion

Monatomic Ions For the transition metals, you must memorize the possible charges of the common ions Cr2+ Chromium (II) ion Chromous ion Cr3+ Chromium (III) ion Chromic ion Mn2+ Manganese (II) ion Manganous ion Mn3+ Manganese (III) ion Manganic ion Fe2+ Iron (II) ion Ferrous ion Fe3+ Iron (III) ion Ferric ion

Monatomic Ions Co2+ Cobalt (II) ion Cobaltous ion Co3+ Cobalt (III) ion Cobaltic ion Ni2+ Nickel (II) ion Nickelous ion Ni3+ Nickel (III) ion Nickelic ion Cu1+ Copper (I) ion Cuprous ion Cu2+ Copper (II) ion Cupric ion Hg22+ Mercury (I) ion Mercurous ion Hg2+ Mercury (II) ion Mercuric ion

Monatomic Ions Sn2+ Tin (II) ion Stannous ion Sn4+ Tin (IV) ion Stannic ion Pb2+ Lead (II) ion Plumbous ion Pb4+ Lead (IV) ion Plumbic ion Ag1+ Silver ion Zn2+ Zinc ion Cd2+ Cadmium ion

Polyatomic Ions Refer to handout Know the formula (that means elements, subscripts, and charge) of each listed

Making Ionic Compounds A cation and an anion will bond in order to bring the charge of the compound to zero. A “criss-cross” method is used to determine the number of each ion necessary to balance the charges Always reduce subscripts.

Making Ionic Compounds Na1+ Cl1- 1 = NaCl Mg2+ Cl1- 1 2 = MgCl2 Al3+ Cl1- 1 3 = AlCl3

Making Ionic Compounds NaCl sodium chloride MgCl2 magnesium chloride AlCl3 aluminum chloride

Making Ionic Compounds Na1+ S 2- 2 1 = Na2S Mg2+ O 2- 2 = MgO Ca2+ P 3- 3 2 = Ca3P2

Making Ionic Compounds Na2S sodium sulfide MgO magnesium oxide Ca3P2 calcium phosphide

Making Ionic Compounds Pb4+ O 2- 2 4 = PbO2 Ag1+ I 1- 1 = AgI Fe3+ O 2- = Fe2O3 2 3

Making Ionic Compounds PbO2 Lead (IV) oxide or plumbic oxide AgI silver iodide iron (III) oxide or ferric oxide Fe2O3

Making Ionic Compounds Pb4+ (OH)1- = Pb(OH)4 1 4 Mg2+ (SO4)2- = MgSO4 2 2 Al3+ (C2O4)2- = Al2(C2O4)3 2 3

Making Ionic Compounds Pb(OH)4 lead (IV) hydroxide or plumbic hydroxide MgSO4 magnesium sulfate Al2(C2O4)3 aluminum oxalate

Crystal Lattice 3-dimensional arrangement of atoms or ions in a solid Simplest part is called a unit cell There are six types of crystal systems We will focus on the cubic unit cell

Cubic Unit Cells Three types: Simple Body-centered Face-centered

Simple Cubic Unit Cell P

Face-centered Cubic Unit Cell NaCl Cl- ions Na+ ions

Body-centered Cubic Unit Cell CsCl Cs+ ion Cl- ion

Now… PRACTICE