Ions and Ionic Compounds Chapter 5 5-1 Simple Ions

Valence Electrons Electrons in the outer energy level

The Octet Rule

Valence electrons and the Periodic Table

Chemical Reactivity How reactive an element is Depends on the electron configuration Notice the Noble gases

Noble Gases Filled s and p sublevels ns2 np6 Least Reactive elements Filled outer energy levels Noble Gases Filled s and p sublevels ns2 np6

Alkali Metals and Halogens The most reactive elements Alkali Metals, 1 valence electron Halogens, seven valence electrons

Lewis Dot Diagram Lewis Dot, or Electron Dot Diagram

Ions Atoms Gain or Lose Electrons to Form Stable Ions (Have the same electron configuration of a noble gas)

Characteristics of Stable Ions Some Ions have noble gas configurations, but are not like noble gases Ions have a charge and so they form compounds Noble gases are very unreactive

Some stable Ions do NOT have noble gas configurations Mainly the transition metals Lose valence electrons Some form more than 1 stable ion

Ions have different properties from parent atoms Sodium and Chlorine are both dangerous But the ions together make table salt

Ions from metals and non-metals Form cations (positive) Form anions (negative)

Ionic Bonding and Salts 5-2

Ionic Bonding Electrons are transferred Ionic Compound

Ionic Bonding Ionic Bonds form between ions of opposite charge Forms Salts

Ionic bonds from between metals and non-metals Form cations (positive) Form anions (negative)

Transferring electrons involves energy change Removing an electron requires energy (ionization energy) Adding an electron releases energy (electron affinity)

Ionic Bonding and Energy The net result of ionic bond formation is the release of energy (exothermic) Called Lattice Energy

Lattice Energy A measure of the strength of an ionic bond The greater the lattice energy, the stronger the bond

Salt Crystals The ions in a salt form a repeating pattern called a crystal lattice The smallest repeating unit is called a unit cell

Ionic Compounds Do not consist of molecules Each cation is surrounded by 6 anions and vise versa

Ionic Compound Crystals In a ratio that results in the compound having no charge (electroneutral)

Ionic Bonds are Strong Stronger than molecular (covalent) bonds (like water) Takes more energy to break them Results in high melting and boiling points

Names and Formulas of Ionic Compounds Section 5-3

Ionic bonds from between metals and non-metals Form cations (positive) Form anions (negative)

Writing Ionic Formulas Ionic compounds are always electroneutral The formula for the compound is written thusly

Rules for Naming Simple (monatomic) Ions Naming the cation The name of the cation is the name of the element Sodium atom makes a sodium ion Some elements (transition metals) have more than 1 ion Use roman numerals to indicate the charge Copper (II) ion or Copper (I) ion have charge of Cu+2 or Cu+ Iron (II) ion or Iron (III) ion

Naming simple ionic compounds The cation followed by the anion with –ide on the end

Naming Ionic Compounds Say the names of these compounds

Polyatomic Ions A charged group of two or more bonded atoms Hydroxide

Names of Polyatomic Ions The endings –ite and –ate indicate oxygen If more than one, -ite is the lesser and –ate is more oxygen

Presence of Hydrogen Name starts with hydrogen Prefixes mono- and di-

Naming Compounds with Polyatomic Ions