Tonight’s Homework:

1. Tonight’s Homework: • Read section 9.1 and do problem 12 on page 247.

2. Covalent Bonds

3. Covalent Bonds • The positive nucleus of one atom attracts the negative electrons of the other atom.

4. Covalent Bonds • The atoms move closer.

5. Covalent Bonds • If they get too close, the positive nuclei repel each other.

6. Covalent Bonds • There is a balance point where the attraction and the repulsion cancel out.

7. Covalent Bonds • Atoms will stay at this balance point. • They have a stable bond. • They are a molecule.

8. Covalent Bonds • Atoms in a covalent bond don’t give away electrons or take them from other atoms. • In a covalent bond, atoms share electrons.

9. Covalent Bonds • F F • Both atoms want one more electron.

10. Covalent Bonds • F F • They can share these two.

11. Covalent Bonds • F F • Now both atoms are happy.

12. Covalent Bonds • F F • This atom has eight outer electrons.

13. Covalent Bonds • F F • So does this one.

14. Covalent Bonds • F F • A dot diagram for a molecule is called a Lewis structure

15. Covalent Bonds • F-F • The pair of shared electrons • can be drawn as a line.

16. Covalent Bonds • O O • Oxygen wants two more electrons.

17. Covalent Bonds • O O • They’ll share this pair...

18. Covalent Bonds • O O • …and this pair.

19. Covalent Bonds • O O • Oxygen atoms share two pairs • of electrons.

20. Covalent Bonds • O O • Again, both atoms seem like they have eight outer electrons.

21. Covalent Bonds • O O • Again, both atoms seem like they have eight outer electrons.

22. Covalent Bonds • O=O • They have a double bond, which can be drawn as two lines.

23. Covalent Bonds • N N • Nitrogen wants three more electrons.

24. Covalent Bonds • N N • Nitrogen wants three more electrons.

25. Covalent Bonds • N N • A nitrogen molecule has a • triple bond.

26. Covalent Bonds • N≡N • A nitrogen molecule has a • triple bond.

27. Covalent Bonds • H • Hydrogen often forms covalent bonds with other elements.

28. Covalent Bonds • H O H • Hydrogen often forms covalent bonds with other elements.

29. Covalent Bonds • H O H • Hydrogen often forms covalent bonds with other elements.

30. Covalent Bonds • H-O-H • Hydrogen often forms covalent bonds with other elements.

31. You try some! • Draw the Lewis structure for the molecule • PH3

32. You try some! • Draw the Lewis structure for the molecule • H-P-H • H

33. You try some! • Draw the Lewis structure for the molecule • H2S

34. You try some! • Draw the Lewis structure for the molecule • H-S-H

35. You try some! • Draw the Lewis structure for the molecule • HCl

36. You try some! • Draw the Lewis structure for the molecule • H-Cl

37. You try some! • Draw the Lewis structure for the molecule • CCl4

38. You try some! • Draw the Lewis structure for the molecule • Cl • Cl-C-Cl • Cl

39. You try some! • Draw the Lewis structure for the molecule • SiH4

40. You try some! • Draw the Lewis structure for the molecule • H • H-Si-H • H

41. Tonight’s Homework: • Read section 9.1 and do problem 12 on page 247.