Types of Bonds

1. Types of Bonds A. Electronegativity - The ability of an atom to attract electrons to itself in a bond 1. Periodic Trends (link to size) Metals – Low Electronegativity Non- Metals – High Electroneg The smaller the atom, the higher the electronegativity

2. Types of Bonds • Molecular Compounds (non-metals) • Sharing of electrons • Covalent or polar covalent bonds • Ex: H2 b. Ionic Compounds (metal + non-metal) • Exchange (stealing) of electrons • Ex: NaCl

6. Types of Bonds 3. Types of bonds Electronegatvity Difference Example: Na-F

7. Types of Bonds Are the following bonds ionic, polar covalent or covalent? Ba – Br C – N Be – F B – H O – H Be – Cl P – H C – H O – O

8. Ionic Ionic – Electron is completely removed from one atom and goes to another a. Metal – Low e-neg (loses e-) b. Non-metal – high e-neg (gains e-)

11. Common Charges

12. Complete the following chart:

13. Ionic Solids • Not Separate molecules • Crystal Lattice – Regular 3D pattern in an ionic solid

15. Ionic Solids at lattice points ions at lattice points

16. Ions in Water • Water (molecule) dissolves salt (ionic crystal):

19. Other Salts Many ionic compounds are called salts CaCl2 Calcium Chloride (Quik-Joe) NaHCO3 Sodium bicarbonate(Baking soda) NaF Sodium Fluoride (toothpaste) CaCO3 Calcium Carbonate(Chalk, antacid) NaOH Sodium Hydroxide (Drano) MgSO4 Magnesium Sulfate(Epsom Salts) All big clumps (crystals) of Ions

20. What is a Molecule? • Group of atoms held together by covalent and polar covalent bonds (SHARING) • Usually composed of non-metals • Stronger than Ionic bonds • Separate (discrete) groups of atoms

22. Old School Lewis Dots A. Single Bonds (LD and Stick) CH4 H2O (bonded versus lone pairs)

23. The Lone Pear(Pair) rides again!

24. Old School Lewis Dots N and H P and F Cl and O NH2CH3

25. Old School Lewis Dots You try: As and H N and Br CH3CH2OH NH2CH2SiCl3 CH3OCH3

26. Old School Lewis Dots B. Multiple Bonds CO2 C2H2

27. Old School Lewis Dots You Try: HCN N2 AlN O2

28. Lewis Dots Rules 1. Sum all valence electrons, including charges 2. Single Bonds 3. Outer atoms get an octet except H 4. Center gets rest even if it violates the octet 5. Double/triple bonds if center atom still does not have an octet

29. Lewis Dots NH3 NCl3 SF6 Br2O ClF5

30. You try: SF4 KrF4 Cl2O ClF3 H2SO4

31. Lewis Dots CO2 HCN CN- ICl4- NO+

32. Lewis Dots You try: C2H4 CO32- H3O+ NH4+ PO43-

33. Less Than an Octet • Hydrogen only makes one bond • Gr I, II and III • Especially if with a halogen BeCl2 BCl3 AlCl3

34. More Than an Octet • Non-Metals starting with P

35. PCl5

36. Resonance Structures Warm-Up: O3 Definition – When a molecule can exist in more than one arrangement of electrons 1. Atoms don’t move 2. Only the electrons (double bonds) move 3. Also called “delocalized bonding”

37. Resonance Structures SPECIAL NOTE: Oxygen rarely makes three bonds for resonance structures. Those structures are not common.

38. PO3- HSO3+

39. Resonance Structures Examples 1. NO2-, CO32-, CHO2-,HNO3 2. Which needs resonance, SO3 or SO32-

40. Shapes of Molecules • Valence Shell Electron Pair Repulsion Theory (VSEPR) • VSEPR – Valence electron pairs on the central atom push as far apart as possible.

42. Shapes of Molecules 1. Linear (180o) BeH2 CO2

43. Shapes of Molecules

44. Shapes of Molecules 2. Trigonal Planar (120o) NO3-

45. Shapes of Molecules

46. Shapes of Molecules 3. Tetrahedral (109.5o) CH4

47. Shapes of Molecules

50. Shapes of Molecules 4. Trigonal Pyramidal (~107o) NH3