IIIIIIIV Chemical Bonding Ionic Bonding

Valence Electrons yValence Electrons – outer energy level electrons involved in bonding

Lewis Structures zElectron Dot Diagrams yshow valence e - as dots ydistribute dots like arrows in an orbital diagram y4 sides = 1 s-orbital, 3 p-orbitals yEX: oxygen 2s2p O X

Lewis Structures zOctet Rule yMost atoms form bonds in order to obtain 8 valence e - yFull energy level = stability ~ Noble Gases Ne

Chemical Bonds zWhy do chemical bonds form? yattractive force between atoms or ions binds them together as a unit ybonds form in order to… xdecrease potential energy (PE) xincrease stability

Properties of Ionic Compounds Bond Formation Electrons are transferred from metal to nonmetal Type of StructureCrystal Lattice Physical StateSolid Melting PointHigh Solubility in WaterYes Electrical ConductivityYes

Lewis Structures Ionic Bonding – Electrons are transferred from the metal atom to the nonmetal atom.

Lewis Structures zIonic – the arrow shows the transfer of e -

Vocabulary CHEMICAL FORMULA Formula Unit IONIC NaCl

Vocabulary COMPOUND Ternary Compound Binary Compound 2 elements more than 2 elements NaNO 3 NaCl

Vocabulary ION Polyatomic Ion Monatomic Ion 1 atom 2 or more atoms NO 3 - Na +

/ Common Ion Charges yAlso called Oxidation Numbers

Common Ion Charges What do the common ion charges tell you? zThe number of electrons that are either lost/gained or transferred in order to form an ionic bond. zFor example: Na  has a charge of +1, this means that Na will lose or transfer one electron to the non-metal ion when bonding.

When bonding, will the following atoms lose or gain electrons? How many? zPotassium zOxygen zFluorine zCalcium Lose 1 Gain 2 Gain 1 Lose 2

Ionic Nomenclature Writing Ionic Formulas zWrite the cation first then the anion. Don’t show charges in the final formula. zOverall charge must equal zero. yIf charges cancel, just write symbols. yIf not, use subscripts to balance charges.

zpotassium chloride zmagnesium oxide zCalcium fluoride  K + Cl   Mg 2+ O 2   Ca 2+ Fl   KCl  MgO  CaFl 2 Ionic Nomenclature

Writing Names of Ionic Compounds zWrite the names of the cation first. zChange ending of the anion to -ide.

zNaBr zK 2 S zCaI 2 ysodium bromide yPotassium sulfide yCalcium iodide Ionic Nomenclature

More on writing Names of Ionic Compounds zPolyatomic ions have special names. zStock System - Use Roman numerals to show the ion’s charge for transition metals. Overall charge must equal zero.

zNaNO 3 zK 2 SO 4 zNH 4 NO 3 ysodium nitrate yPotassium sulfate yAmmonium nitrate Ionic Nomenclature

zFe 2 S zCuSO 4 zCoCl 2 yIron(I)sulfide yCopper(II)sulfate yCobalt(II)chloride Ionic Nomenclature