1 / 48

Chemical Bonding

Chemical Bonding. Chemical Bond attractive force between atoms or ions that binds them together as a unit bonds form in order to… decrease potential energy (PE) increase stability. COMPOUND. more than 2 elements. 2 elements. Binary Compound. Ternary Compound. NaCl. NaNO 3. ION.

gyula
Download Presentation

Chemical Bonding

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chemical Bonding

  2. Chemical Bond • attractive force between atoms or ions that binds them together as a unit • bonds form in order to… • decrease potential energy (PE) • increase stability

  3. COMPOUND more than 2 elements 2 elements Binary Compound Ternary Compound NaCl NaNO3

  4. ION 2 or more atoms 1 atom Monatomic Ion Polyatomic Ion Na+ NO3-

  5. Types of Bonds COVALENT IONIC e- are transferred from metal to nonmetal e- are shared between two nonmetals Bond Formation Type of Structure true molecules crystal lattice Physical State liquid or gas solid Melting Point low high Solubility in Water yes usually not yes (solution or liquid) Electrical Conductivity no Other Properties odorous

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

  7. Ionic Bonds

  8. Ionic Bonding - Crystal Lattice

  9. Covalent Bonding - True Molecules Diatomic Molecule

  10. Metallic Bonding - “Electron Sea”

  11. Bond Polarity • Most bonds are a blend of ionic and covalent characteristics. • Difference in electronegativity determines bond type.

  12. Bond Polarity Electronegativity • Attraction an atom has for a shared pair of electrons. • higher e-neg atom  - • lower e-neg atom +

  13. Bond Polarity Electronegativity Trend (p. 151) Increases up and to the right.

  14. Bond Polarity Nonpolar Covalent Bond e- are shared equally symmetrical e- density usually identical atoms

  15. - + • Polar Covalent Bond • e- are shared unequally • asymmetrical e- density • results in partial charges (dipole)

  16. Nonpolar Polar Ionic

  17. Bond Polarity Examples: Cl2 HCl NaCl 3.0-3.0=0.0 Nonpolar 3.0-2.1=0.9 Polar 3.0-0.9=2.1 Ionic

  18. Chemical Bond • attractive force between atoms or ions that binds them together as a unit • bonds form in order to… • decrease potential energy (PE) • increase stability

  19. Lewis Diagrams Molecular Structure

  20. Rule • Remember… • Most atoms form bonds in order to have 8 valence electrons.

  21. F F F S F F F F B F F H O H N O Very unstable!! A. Octet Rule • Exceptions: • Hydrogen  2 valence e- • Groups 1,2,3 get 2,4,6 valence e- • Expanded octet  more than 8 valence e- (e.g. S, P, Xe) • Radicals  odd # of valence e-

  22. B. Drawing Lewis Diagrams • Find total # of valence e-. • Arrange atoms - singular atom is usually in the middle. • Form bonds between atoms (2 e-). • Distribute remaining e- to give each atom an octet (recall exceptions). • If there aren’t enough e- to go around, form double or triple bonds.

  23. B. Drawing Lewis Diagrams • CF4 1 C × 4e- = 4e- 4 F × 7e- = 28e- 32e- F F C F F - 8e- 24e-

  24. B. Drawing Lewis Diagrams • BeCl2 1 Be × 2e- = 2e- 2 Cl × 7e- = 14e- 16e- ClBeCl - 4e- 12e-

  25. B. Drawing Lewis Diagrams • CO2 1 C × 4e- = 4e- 2 O × 6e- = 12e- 16e- OCO - 4e- 12e-

  26. C. Polyatomic Ions • To find total # of valence e-: • Add 1e- for each negative charge. • Subtract 1e- for each positive charge. • Place brackets around the ion and label the charge.

  27. C. Polyatomic Ions • ClO4- 1 Cl × 7e- = 7e- 4 O × 6e- = 24e- 31e- O O Cl O O + 1e- 32e- - 8e- 24e-

  28. C. Polyatomic Ions • NH4+ 1 N × 5e- = 5e- 4 H × 1e- = 4e- 9e- H H N H H - 1e- 8e- - 8e- 0e-

  29. C. Polyatomic Ions • OH- 1 O × 6e-= 6e- 1 H × 1e- = 1e- 7e- O H + 1e- 8e- - 8e- 0e-

  30. D. Resonance Structures • Molecules that can’t be correctly represented by a single Lewis diagram. • Actual structure is an average of all the possibilities. • Show possible structures separated by a double-headed arrow.

  31. O O S O O O S O O O S O D. Resonance Structures • SO3

  32. Molecular Geometry

  33. VSEPR Theory • Valence Shell Electron Pair Repulsion Theory • Electron pairs orient themselves in order to minimize repulsive forces.

  34. Lone pairs repel more strongly than bonding pairs!!! VSEPR Theory • Types of e- Pairs • Bonding pairs - form bonds • Lone pairs - nonbonding e-

  35. Bond Angle VSEPR Theory • Lone pairs reduce the bond angle between atoms.

  36. Know the 8 common shapes & their bond angles! Determining Molecular Shape • Draw the Lewis Diagram. • Tally up e- pairs on central atom. • double/triple bonds = ONE pair • Shape is determined by the # of bonding pairs and lone pairs.

  37. BeH2 Common Molecular Shapes 2 total 2 bond 0 lone LINEAR 180°

  38. BF3 Common Molecular Shapes 3 total 3 bond 0 lone TRIGONAL PLANAR 120°

  39. SO2 Common Molecular Shapes 3 total 2 bond 1 lone BENT <120°

  40. CH4 Common Molecular Shapes 4 total 4 bond 0 lone TETRAHEDRAL 109.5°

  41. NH3 Common Molecular Shapes 4 total 3 bond 1 lone TRIGONAL PYRAMIDAL 107°

  42. H2O Common Molecular Shapes 4 total 2 bond 2 lone BENT 104.5°

  43. PCl5 Common Molecular Shapes 5 total 5 bond 0 lone TRIGONAL BIPYRAMIDAL 120°/90°

  44. SF6 Common Molecular Shapes 6 total 6 bond 0 lone OCTAHEDRAL 90°

  45. F P F F Examples • PF3 4 total 3 bond 1 lone TRIGONAL PYRAMIDAL 107°

  46. OCO Examples • CO2 2 total 2 bond 0 lone LINEAR 180°

More Related