1. Chapter 3 Chemical Bonds Chemistry B11

2. 1.Ionic bonds 2. Covalent bonds 3. Metallic bonds 4. Hydrogen bonds 5. Van der Waals forces Chemical Bonds

3. 1.Ionic bonds 2. Covalent bonds Chemical Bonds

4. Review Shell 1 Main-group elements 1A – 8A Maximum 2 electrons in valence shell Hydrogen and Helium Other Shells Maximum 8 electrons in valence shell

5. Octet rule Goal of atoms Filled valence shell Noble gases (Stable) Na + : 1s 2 2s 2 2p 6 + e - Na: 1s 2 2s 2 2p 6 3s 1 Ne: 1s 2 2s 2 2p 6 Ar: 1s 2 2s 2 2p 6 3s 2 3p 6

6. Octet rule Goal of atoms Filled valence shell + e - Ar: 1s 2 2s 2 2p 6 3s 2 3p 6 Noble gases (Stable) Cl: 1s 2 2s 2 2p 6 3s 2 3p 5 Cl - : 1s 2 2s 2 2p 6 3s 2 3p 6 Na + : 1s 2 2s 2 2p 6 + e - Na: 1s 2 2s 2 2p 6 3s 1 Ne: 1s 2 2s 2 2p 6

7. Octet rule Goal of atoms Filled valence shell Noble gases (Stable) Mg 2+ : 1s 2 2s 2 2p 6 + 2e - Mg: 1s 2 2s 2 2p 6 3s 2 Ne: 1s 2 2s 2 2p 6

8. Octet rule Goal of atoms Filled valence shell Noble gases (Stable) Mg 2+ : 1s 2 2s 2 2p 6 + 2e - Mg: 1s 2 2s 2 2p 6 3s 2 Ne: 1s 2 2s 2 2p 6 + 2e - O: 1s 2 2s 2 2p 4 O 2- : 1s 2 2s 2 2p 6 Ne: 1s 2 2s 2 2p 6

9. Metals: lose 1, 2 or 3 e - Cation (Y + ) Nonmetals: gain 1, 2 or 3 e - Anion (X - ) Ions Cation (Y + ): Na + Li + Ca 2+ Al 3+ Anion (X - ): Cl - F - O 2- Number of protons and neutrons in the nucleus remains unchanged.

10. Transition elements 1A2A 3A 4A5A6A7A 8A

11. Two problems of Octet rule 1. The octet rule cannot be used for transition and inner transition elements. Fe 2+ Fe 3+ Cu 1+ Cu 2+ 2. Ions of period 1 and 2 elements with charges greater than +2 are unstable. C 4+ C 4- B 3+ C B unstable

12. Naming Monatomic Cations International Union of Pure and Applied Chemistry (IUPAC) systematic names Name of the metal + “ion” H + Hydrogen ion Li + Lithium ion Ca 2+ Calcium ion Al 3+ Aluminum ion Cu 1+ Copper(I) ion Cu 2+ Copper(II) ion Fe 2+ Iron(II) ion Fe 3+ Iron(III) ion Hg + Mercury(I) ion Hg 2+ Mercury(II) ion Sn 2+ Tin(II) ion Sn 4+ Tin(IV) ion

13. Naming Monatomic Cations common name Name of the metal + “-ous”smaller charge “-ic”larger charge Cu 1+ Copper(I) ionCuprous ion Cu 2+ Copper(II) ionCupric ion Fe 2+ Iron(II) ion Ferrous ion Fe 3+ Iron(III) ion Ferric ion Hg + Mercury(I) ion Mercurous ion Hg 2+ Mercury(II) ion Mercuric ion Sn 2+ Tin(II) ionStannous ion Sn 4+ Tin(IV) ionStannic ion

14. Naming Monatomic Anions Stem part of the name + “-ide” AnionStem nameAnion name F-F- fluorFluoride ion Cl - chlorChloride ion Br - bromBromide ion I-I- iodIodide ion O 2- oxOxide ion S 2- sulfSulfide ion P 3- phosphPhosphide ion N 3- nitrNitride ion

15. Naming Polyatomic Ions Cation: NH 4 + Ammonium Anion: OH - Hydroxide NO 2 - Nitrite NO 3 - Nitrate SO 3 2- Sulfite SO 4 2- Sulfate HSO 3 - Hydrogen Sulfite (bisulfite) HSO 4 - Hydrogen sulfate (bisulfate) MnO 4 - Permanganate CrO 4 2- Chromate Cr 2 O 7 2- Dichromate CO 3 2- Carbonate HCO 3 - Hydrogen Carbonate (bicarbonate) PO 3 3- Phosphite PO 4 3- Phosphate HPO 4 2- Hydrogen phosphate H 2 PO 4 - Dihydrogen phosphate

16. Ionic bonds Metal-Nonmetal Na: 1s 2 2s 2 2p 6 3s 1 Cl: 1s 2 2s 2 2p 6 3s 2 3p 5 Anion Cation Na + : 1s 2 2s 2 2p 6 Cl - : 1s 2 2s 2 2p 6 3s 2 3p 6

17. Sodium (Na) NaCl Chlorine (Cl)

18. matter are neutral (uncharged): total number of positive charges = total number of negative charges Na + Cl - NaCl Ca 2+ Cl - CaCl 2 Al 3+ S 2- Al 2 S 3 Ba 2+ O 2- Ba 2 O 2 BaO Molecule of NaCl Formula of NaCl

19. matter are neutral (uncharged): total number of positive charges = total number of negative charges Na + NO 3 - NaNO 3 Ca 2+ CO 3 2- Ca 2 (CO 3 ) 2 Ca(CO 3 ) Al 3+ SO 4 2- Al 2 (SO 4 ) 3 Mg 2+ NO 2 - Mg(NO 2 ) 2

20. Naming Binary Ionic compounds name of metal (cation) + name of anion NaClsodium chloride CaOcalcium oxide Cu 2 Ocopper(I) oxidecuprous oxide CuOcopper(II) oxidecupric oxide Naming Polyatomic Ionic compounds BaCO 3 barium carbonate Li 2 SO 4 lithium sulfateLi 2 SO 3 lithium sulfite

21. Covalent bonds Nonmetal-Nonmetal Metalloid-Nonmetal Sharing of valence electrons

22. Lewis Dot Structure H He Li C Al NCl H H Or H H Cl H Lewis Structure H Cl Cl: 1s 2 2s 2 2p 6 3s 2 3p 5 H: 1s 1 He: 1s 2 Ar: 1s 2 2s 2 2p 6 3s 2 3p 6

23. H Cl x Shared pair of electrons (bonding pair of electrons) Unshared pair of electrons (nonbonding pair of electrons) - (Lone pair) Only valance electrons are involved in bonding (ionic and covalent bonds).

24. Electronegativity A measure of an atom’s attraction for the electrons Electronegativity Ionization energy

25. Covalent bonds Nonpolar covalent bond: electrons are shared equally. Polar covalent bond: electrons are shared unequally. HCl δ+ δ- Dipole

26. Electronegativity & bonds Electronegativity Difference Between Bonded AtomsType of Bond Less than 0.5Nonpolar Covalent 0.5 to 1.9Polar Covalent Greater than 1.9Ionic H H 2.1 – 2.1 = 0 Nonpolar covalent N H 3.0 – 2.1 = 0.9 polar covalent Na F 4.0 – 0.9 = 3.1 Ionic

27. Covalent compounds H – C – H – O CH 2 O H C H O H – C – H – O H C H O – Correct H C H H H H – C – H – H – H CH 4 H – N – H – H NH 3 H N H H

28. H C CH C – C C2H4C2H4 H H H H H H H C CH C = C H H H H H H H C CH H – C – C – H C2H2C2H2 H C CH H – C C – H Correct

29. Naming Binary Covalent compounds Mono – Di – Tri – Tetra– Penta – Hexa – Hepta – Octa – Nona – Deca 1.Don’t use “mono” for the 1 st element. 2.Drop the “a” when followed by a vowel. NO 2 nitrogen dioxide N 2 O 4 dinitrogen tetroxide CCl 4 carbon tetrachloride S 2 O 3 disulfur trioxide prefix and full name of the first element in formula + prefix and the anion name of the second element + “ide”

30. VSEPR Model VSEPR: Valence-Shell Electron-Pair Repulsion method Bond angle: angle between two atoms bonded to a central atom. Each region of electron likes to be as far away as possible from the others.

31. Regions of electron density Four regions of electron density around an atom:

32. Bond Angles in covalent molecules Linear molecules Trigonal planar molecules Tetrahedral molecules 2 regions 3 regions 4 regions

33. Unshared electron paires H2OH2O CH 4 NH 3

34. Polarity 1.Molecule has polar bonds. 2.Its centers of δ+ and δ- lie at different places (sides). O = C = O δ- δ+ δ- nonpolar molecule H – C – H – H – H δ+ δ- C = O H H δ+ δ- polar molecule N H H H δ- δ+