1. IIIIIIIV Chemical Bonding Covalent / Molecular Compounds

2. Properties of Covalent Bonds Bond FormationElectrons shared between two nonmetals Type of StructureTrue Molecules Physical StateLiquid or Gas Melting PointLow Solubility in WaterUsually not Electrical ConductivityNo Other PropertiesOdorous

3. Covalent Bonding - True Molecules RETURN Types of Bonds Diatomic Molecule

4. zNonpolar Covalent Bond ye - are shared equally ysymmetrical e - density yusually identical atoms Bond Polarity

5. NOF Cl Br I H Nonpolar Covalent Molecules zThe Seven Diatomic Elements Br 2 I 2 N 2 Cl 2 H 2 O 2 F 2

6. ++ -- Bond Polarity zPolar Covalent Bond ye - are shared unequally yasymmetrical e - density yresults in partial charges (dipole)

7. Bond Polarity zRemember, most bonds are a blend of ionic and covalent characteristics. zDifference in electronegativity determines bond type.

8. Bond Polarity Examples: zCl 2 zHCl zNaCl 3.0-3.0=0.0 Nonpolar 3.0-2.1=0.9 Polar 3.0-0.9=2.1 Ionic

9. ++ -- ++ Lewis Structures zNonpolar Covalent - no charges zPolar Covalent - partial charges

10. Naming Covalent Compounds zPrefix System (binary compounds) 1.Less e - neg atom comes first. 2.Add prefixes to indicate # of atoms. Omit mono- prefix on first element. 3.Change the ending of the second element to -ide.

11. PREFIX mono- di- tri- tetra- penta- hexa- hepta- octa- nona- deca- NUMBER 1 2 3 4 5 6 7 8 9 10 Molecular Nomenclature

12. zCCl 4 zN 2 O zSF 6 ycarbon tetrachloride ydinitrogen monoxide ysulfur hexafluoride Molecular Nomenclature

13. zarsenic trichloride zdinitrogen pentoxide ztetraphosphorus decoxide yAsCl 3 yN2O5yN2O5 yP 4 O 10 Molecular Nomenclature

14. Metallic Bonding

15. “electron sea” METALLIC Bond Formation Type of Structure Solubility in Water Electrical Conductivity Other Properties Melting Point Properties of Metallic Bonds Physical State e - are delocalized among metal atoms very high yes (any form) no malleable, ductile, lustrous solid

16. Metallic Bonds zMetal atoms are held together in the solid through metallic bonding. zMetals hold on to their valence electrons very weakly. zThink of them as positive ions (cations) floating in a sea of electrons.

17. Sea of Electrons ++++ ++++ ++++ zElectrons are free to move through the solid. zThis is why metals are able to conduct electricity.

18. Metals are… zMetals are malleable - hammered into shape (bend). zAlso ductile - drawn into wires. zBoth malleability and ductility demonstrate the mobility of the valence electrons

19. Intermolecular Forces

20. Intramolecular vs Intermolecular zIntramolecular - forces that hold particles together in ionic, covalent and metallic bonds zIntermolecular - attractions between one molecule and a neighboring molecule.

21. Intermolecular Forces zTypes of intermolecular forces: yDispersion forces yDipole-dipole yHydrogen bonds

22. Dispersion forces zWeak forces that result from temporary shifts in the density of electrons in electron clouds, creating an induced dipole. zWeakest of the intermolecular forces zExists between identical atoms

23. Dipole-dipole forces zAttractions between oppositely charged regions of polar molecules zStronger than dispersion forces zExists between polar covalent molecules

24. Hydrogen bonding zSpecial type of dipole-dipole attraction that occurs between molecules containing a hydrogen atom bonded to a small, highly electronegative atom with at least one lone electron pair. zOccurs between hydrogen and either fluorine, oxygen, and nitrogen atoms only. zStrongest of the forces

25. Hydrogen bonding

26. Properties of Hydrogen Bonding zStronger forces=higher melting/boiling points zWeaker forces=lower melting/boiling points