COVALENT BONDING

1. COVALENT BONDING Chapter 16

2. AND THE SUBJECTS ARE… THE NAME IS BOND, COVALENT BOND SINGLES, DOUBLES & TRIPPPLES COORDINATE COVALENT BONDS RESONATE THIS! THERE’S ALWAYS AN EXCEPTION PRINCESS VSEPR HYBRIDS DISSOCIATIONS AND ATTRACTIONS

3. YOU KNOW THAT YOU MAY BE A COVALENT BOND WHEN… ELECTROSTATIC FORCES ARE WEAK r ELECTRONEGATIVITY IS SMALL THERE ARE NO METAL CATIONS IONS DON’T GET OR LOSE ELECTRONS

4. SINGLE COVALENT BOND HYDROGEN H· + ·H  H:H Hydrogen Hydrogen Hydrogen Atom Atom molecule HYDROGEN ATOMS FORM SINGLE BONDS Shared electron pair

5. SINGLE COVALENT BOND DIATOMIC MOLECULES HYDROGEN NITROGEN OXYGEN FLUORINE CHLORINE BROMINE IODINE r ELECTRONEGATIVITY = 0 SHARED ELECTRONS

6. SINGLE COVALENT BOND FOR CHLORINE, 1s 2s 2p 3s 3p Cl ↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑_ Cl ↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓_↓

7. SINGLE COVALENT BONDDEFINITIONS EMPIRICAL FORMULA - LOWEST WHOLE NUMBER RATIO OF ELEMENTS IN A COMPOUND MOLECULAR FORMULA – SHOWS ACTUAL NUMBER AND KINDS OF ELEMENTS IN A COMPOUND STRUCTURAL FORMULA – SHOWS ARRANGEMENT OF ATOMS IN A COMPOUND

8. SINGLE COVALENT BOND

9. SINGLE COVALENT BOND ELECTRON PAIRS REPRESENTED BY A LINE BETWEEN 2 ELEMENTS H - H OTHER ELECTRONS MUST BE SHOWN, INCLUDING UNSHARED PAIRS LONE PAIRS NON-BONDING PAIRS

10. 2 CHLORINE ATOMS FORM A COVALENT BOND SINGLE COVALENT BOND

11. WATER MOLECULE FORMED FROM 1 OXYGEN AND 2 HYDROGEN ATOMS USING COVALENT BONDS SINGLE COVALENT BOND

12. SINGLE COVALENT BOND CARBON FORMS UP TO 4 BONDS C ↑↓↑↓↑_↑_ 1s 2s 2p TO MAKE THE 4TH BOND, A 2s ELECTRON MOVES TO A 2p ORBITAL C ↑↓↑_↑_↑_↑_ 1s 2s 2p

13. DOUBLE AND TRIPLE COVALENT BONDS

14. CORDINATE COVALENT BONDS BOND FORMED WHEN BOTH ELECTRONS DONATED BY THE SAME ATOM

15. POLYATOMIC IONS POLYATOMIC IONS ARE COVALENTLY BONDED THE CHARGE ON THE ION SHOWS THE NUMBER OF ELECTRONS ADDED OR MISSING

16. RESONANCE RESONANCE STRUCTURES SHOW 2 OR MORE VALID DOT FORMULAS HAVING THE SAME NUMBER OF BONDS AND ELECTRONS

17. EXCEPTIONS to the OCTET RULE IN SOME MOLECULES, THE OCTET RULE CANNOT BE SATISFIED

18. EXCEPTIONS to the OCTET RULE DIAMAGNETIC – ALL ELECTRONS PAIRED PARAMAGNETIC - 1 OR MORE UNPAIRED ELECTRONS EXPANDED OCTET – MAY INCLUDE MORE THAN 8 ELECTRONS

19. MOLECULAR ORBITALS (MO) WHEN 2 ATOMIC ORBITALS OVERLAP, 2 MOLECULAR ORBITALS FORM 1 ORBITAL IS BONDING ENERGY LOWER THAN ATOMIC ORBITAL 1 ORBITAL IS ANTI-BONDING ENERGY HIGHER THAN ATOMIC ORBITAL ORBITAL BELONGS TO MOLECULE AS A WHOLE ORBITAL CONTAINS UP TO 2 ELECTRONS

20. MOLECULAR ORBITALS Anti-bonding Molecular Orbital Atomic Orbital Atomic Orbital Energy Bonding Molecular Orbital

21. MOLECULAR ORBITALSHYDROGEN TWO H2 MOLECULE ELECTRONS OCCUPY A BONDING ORBITAL PROBABILITY OF FINDING ELECTRONS IN THE AREA BETWEEN 2 ATOMS IS HIGH BOND IS SYMETRICAL ALONG AXIS BETWEEN ATOMS CALLED A SIGMA (σ) BOND

22. MOLECULAR ORBITALS H2 Anti-bonding Molecular Orbital Atomic Orbital Atomic Orbital   Energy  Bonding Molecular Orbital

23. MOLECULAR ORBITALS (MO)

24. MOLECULAR ORBITALSHELIUM 2 MOLECULES OF He CANNOT BE FORMED 2 ELECTRONS IN BONDING ORBITAL 2 ELECTRONS IN ANTI-BONDING ORBITAL REPULSIVE FORCES IN ANTI-BONDING ORBITAL NEGATES ATTRACTIVE FORCES IN BONDING ORBITAL

25. MOLECULAR ORBITALS He Anti-bonding Molecular Orbital  Atomic Orbital Atomic Orbital   Energy  Bonding Molecular Orbital

26. MOLECULAR ORBITALS “p” ORBITALS CAN OVERLAP OVERLAP END-TO-END – SIGMA (σ) BOND OVERLAP SIDE-BY-SIDE – PI (P) BOND

27. MOLECULAR ORBITALS

28. MOLECULAR ORBITALS

29. VALENCE SHELL ELECTRON PAIR REPULSION THEORYVSEPR ELECTRON PAIRS REPEL DUE TO THE SAME CHARGE MOLECULAR SHAPE ADJUSTS TO SET FURTHEST DISTANCE BETWEEN PAIRS CREATES 3 DIMENSIONAL STRUCTURES

30. MOLECULES in 3-D METHANE (CH4) CARBON in CENTER, with H in the CORNERS to form a TETRAHEDRON H-C-H ANGLES ARE 109.5°

31. MOLECULES in 3-D MOLECULAR GEOMETRY

32. MOLECULES in 3-D UNSHARED ELECTRON PAIRS IMPACT SHAPE UNSHARED ELECTRONS HELD CLOSER TO NUCLEUS UNSHARED ELECTRONS ALSO MORE STRONGLY REPEL OTHER ATOMS • ANGLE SHIFTS TO 107°

33. MOLECULES in 3-D DIHYDROGEN OXIDE (H2O) MOLECULE BECOMES BENT PLANAR WITH 2 PAIRS UNSHARED ELECTRONS UNSHARED PAIRS REPEL BONDING PAIRS, COMPRESSING ANGLE H-O-H ANGLE IS 105°

34. MOLECULES in 3-D CARBON DIOXIDE (CO2) NO UNSHARED ELECTRON PAIRS IN CARBON DIOXIDE MOLECULE IS LINEAR ANGLE IS 180o

35. MOLECULES in 3-D MOLECULES WITH NO UNPAIRED ELECTRONS, BUT WITH DOUBLE BOND MOLECULE IS TRIAGONAL PLANAR SHAPE

36. HYBRID ORBITALS SEVERAL ATOMIC ORBITALS CAN MIX TO FORM HYBRID ORBITALS EACH ATOM HAS SEPARATE s AND p ORBITALS

37. HYBRID ORBITALS SOME ATOMIC ORBITALS MERGE, FORMING 4 sp3 HYBRID ORBITALS EACH ORBITAL BENDS TOWARD CORNER OF TETRAHEDRON

38. HYBRID ORBITALS METHANE (CH4) s ORBITALS OF HYDROGEN OVERLAP CARBON sp3ORBITAL FORMS σ BONDS

39. HYBRID ORBITALS DOUBLE BONDS ATOMIC ORBITALS IN DOUBLE BONDS MERGE TO FORM 3 sp2 HYBRID ORBITALS & 1 p ORBITAL REMAINS ORBITALS BEND TOWARD CORNER OF TRIANGLE, PERPENDICULAR TO REMAINING p ORBITAL

40. HYBRID ORBITALS ETHYLENE (C2H4) HYDROGEN ORBITALS OVERLAP WITH CARBON sp2ORBITALS 1 sp2 ORBITAL FROM EACH CARBON BONDS REMAINING CARBON p ORBITALS FORM A P BOND

41. HYBRID ORBITALS TRIPLE BONDS ATOMIC ORBITALS MERGE TO FORM 2 sp HYBRID ORBITALS, AND 2 p ORBITALS REMAIN ORBITAL IS LINEAR AND PERPENDICULAR TO REMAINING p ORBITALS

42. HYBRID ORBITALS ACETYLENE (C2H2) HYDROGEN s ORBITALS OVERLAP WITH CARBON sp2 ORBITALS, AND 1CARBON sp2ORBITAL EACH BOND REMAINING CARBON p ORBITALS FORM P BOND

43. POLAR BONDS BOND POLARITY ELECTRONS SHARED IN COVALENT BOND BUT NOT NECESSARILY EQUALLY NON-POLAR BONDS ELECTRONS SHARED EQUALLY POLAR BOND ELECTRONS PULLED STRONGLY TO ATOM WITH HIGHER ELECTRONEGATIVITY

44. POLAR BONDS HYDROGEN IODIDE (HI) IODINE (EN = 2.5) HAS A HIGHER ELECTRONEGATIVITY THAN HYDROGEN (EN = 2.1) ELECTRONS DRAWN TOWARD IODINE NUCLEUS REPRESENTED BY: δ+ δ- H – I or H - I HYDROGEN DEVELOPS PARTIAL POSITIVE CHARGE, WHILE IODINE COUNTERS WITH A PARTIAL NEGATIVE CHARGE

45. POLAR BONDS WATER AND CHLOROMETHANE ARE EXAMPLES OF POLAR MOLECULES

46. POLAR BONDS TYPE OF BOND IS DETERMINED BY THE ELECTRONEGATIVITY OF THE BONDING ELEMENTS

47. POLAR MOLECULES POLAR MOLECULE HAS 1 OR MORE POLAR BONDS CHARGED REGION IS A ‘POLE’ MOLECULE HAVING 2 POLES IS A ‘DIPOLE’ WHEN POLAR MOLECULES ARE PLACED IN AN ELECTRIC FIELD, THEY BECOME ORIENTED WITH RESPECT TO THE FIELD

48. POLAR MOLECULESIN AN ELECTRIC FIELD Positive Plate Negative Plate

49. : : : : O = C = O O : : H H POLAR MOLECULES EFFECT OF POLAR BONDS ON THE MOLECULE’S POLARITY DEPENDS ON SHAPE OF THE MOLECULE AND POLAR BOND ORIENTATION WATER IS A POLAR MOLECULE, BUT CARBON DIOXIDE IS NOT

50. BOND DISSOCIATION ENERGY ENERGY NEEDED TO BREAK A COVALENT BOND