1. Chapter 8

2.  When two atoms both want to gain electrons they cannot form an ionic bond  They can form a covalent bond  Atoms are held together by sharing e -

3.  A neutral group of atoms joined together by covalent bonds  A molecule, consisting of two atoms, is a diatomic molecule  H 2, N 2, O 2, Cl 2, etc.

4.  A compound consisting of two or more molecules  Molecular compounds tend to have lower boiling points (bp) than ionic compounds

5.  Molecular compounds are generally a liquid at room temperature  Ionic compounds are generally a solid

7.  The chemical formula of a molecular compound  Shows how many atoms of each element a molecule contains  C 7 H 2 (NO 2 ) 3

8.  Also describe molecules with one type of element  O 2  N 2

9. H2OH2OC2H6C2H6

10. CO 2 NH 3

11.  p. 216 #1-6

12.  In covalent bonding, e - sharing usually occurs so that the e - configurations of noble gases  Covalent bonding usually occurs between metalloids and nonmetals  Groups 4, 5, 6, and 7

13.  Two atoms held together by sharing a pair of electrons

14.  An e - dot structure such as H:H represents the shared pair of e - of the covalent bond by two dots

15.  Represents the covalent bonds by dashes and shows the arrangement of covalently bonded atoms H - H

16.  A pair of valence electrons that is not shared between atoms

17. 2H + O  O−H + O−H | | H H

18.  NH 3  CH 4

19.  Practice Problems p. 220 # 7-8

20.  Sometimes atoms bond by sharing more than one pair of e -  Atoms can form double or triple bonds

21.  A bond involving two shared pairs of e -

22.  A bond formed by sharing three e -

23. O2N2O2N2

24.  p 222 Table 8.1

25.  Sometimes atoms do not combine ideally  CO – e - configuration

26.  A covalent bond in which one atom donates both bonding electrons  Represented with an arrow

27.  Once formed a coordinate covalent bond is just like any other covalent bond

28.  Tightly bound group of atoms that has a positive or negative charge and behaves as a unit

29.  Sometimes in chemistry we use MAGIC!

30. H + + NH 3  NH 4 + Hydrogen Ammonia Ammonium Ion Molecule Ion

31.  SO 3  How do you find the charge?

32.  p. 225 #9-12  Attempt to do by yourself first  We will go over this!!!!!!

33.  The energy to break a covalent bond  Usually given for 1 mole of molecule  6.02 x 10 23

34.  A large dissociation energy shows a strong covalent bond and vice versa  C-C 347 kJ/mol  C=C 657 kJ/mol  CΞC 908 kJ/mol

35.  Molecules containing bonds with high dissociation energies typically do not react  The bonds are very stable

36.  A structure that can be correctly drawn in two or more valid e - dot structures

39.  Given the structures, what are all the resonance structures  C 3 H 5 -  C 6 H 6

40.  For some molecules or ions it is impossible to draw correct e - dot structures  NO 2

41.  Octet rule cannot be applied to molecules with an odd number of total valence e -

42.  Some molecules will have more or less than 8 valence e -

43.  BF 3  PCl 5  SF 6

44.  p. 229 #13-22  Try #22 we didn’t go over this!

45.  Molecular Orbital  VSEPR  Hybrid Orbital

46.  Two kinds of bonds  Sigma bonds (single)  Pi bonds (double and triple)

51.  Valence-Shell Electron-Pair Repulsion Theory  The repulsion between e - pairs causes them to stay as far apart as possible

52.  This repulsion causes molecules to form specific shapes  p. 213

54.  VSEPR Theory does a great job explaining shape  However, doesn’t explain types of bonds

55.  Gives information about both shape and bonds

57.  p 236 #23-25, 27

58.  In polar bonds e - are not shared equally  Atoms with higher electronegativity attract e - more

59.  One end of the molecule is slightly negative

60.  Van der Waals  London Dispersion  Dipole-Dipole  Hydrogen Bonding

64.  p 244 #32-34, 36, 37

65.  p. 247 #40-47, 49, 51, 54, 58-60