2.  atoms that lose or gain electrons become ions  cations have + charge  anions have – charge  cations and anions are attracted to each other by elecrostatic force.

3.  bonds between ions form repeating patterns  can take the form of crystals when solid  usually a metal with a nonmetal  formula units, NOT molecules

4.  outer electrons (the highest energy level electrons) are called valence electrons.  the most stable valence electron configuration is that of noble gases  every atom will attempt to have its valence electrons conform to noble gas nearest it.  for most elements, this means the atom will have s 2 and p 6 filled when stable

6. Cl 2 Chlorine forms a covalent bond with itself

7. Cl How will two chlorine atoms react?

8. Cl Each chlorine atom “wants” to gain one electron to achieve an octet

9. Cl Neither atom will give up an electron, chlorine is highly electronegative. What’s the solution – what can they do to achieve an octet?

10. Cl

14. octet circle the electrons for each atom that completes their octets

15. Cl circle the electrons for each atom that completes their octets octet

16. Cl The octet is achieved by each atom sharing the electron pair in the middle

17. Cl The octet is achieved by each atom sharing the electron pair in the middle

18. Cl This is the bonding pair

19. Cl It is a single bonding pair. The other electrons are unshared pairs.

20. Cl It is called a SINGLE BOND

21. Cl Single bonds are abbreviated with a dash

22. Cl This is the chlorine molecule, Cl 2

23. O2O2 Oxygen is also one of the diatomic molecules

24. How will two oxygen atoms bond? OO

25. OO Each atom has two unpaired electrons

26. OO

27. OO

28. OO

29. OO

30. OO

31. OO

32. Oxygen atoms are highly electronegative. So both atoms want to gain two electrons. OO

33. Oxygen atoms are highly electronegative. So both atoms want to gain two electrons. OO

34. OO

35. OO

36. OO

37. OO

38. O O Both electron pairs are shared.

39. 6 valence electrons plus 2 shared electrons = full octet O O

40. 6 valence electrons plus 2 shared electrons = full octet O O

41. two bonding pairs, O O making a double bond

42. O O = For convenience, the double bond can be shown as two dashes. O O

43. O O = This is the oxygen molecule, O 2 this is so cool! !

44.  formed by two or more nonmetals  molecules are a neutral group of atoms joined by covalent bonds in order to satisfy the octet rule (there are exceptions to this) › atoms are held together by sharing valence electrons  diatomic molecules are two of the same atoms covalently bonded

47.  atoms of different elements can covalently bond to form molecular compounds › tend to have lower melting and boiling points than ionic compounds

50.  single covalent bond- share a pair of electrons

51.  often there is a pair of valence electrons that are not shared ( unshared pair )

52.  double or triple bonds share two or three pairs of electrons

54.  shows how many atoms of each element › methane is one carbon and four hydrogen › CH 4  does not tell you about the molecule’s structure (structural formula)

57.  refers to the idea that there are two or more valid electron dot formulas for a molecule

58.  prefixes tell how many atoms of each element are present  still end with -ide  vowel of the prefix is often dropped  omit prefix mono- for the first element  carbon monoxide → CO  nitrogen triiodide → NI 3

59. CH 4 methane BCl 3 boron trichloride CO 2 Carbon dioxide

60. NumberPrefix 1mono 2di 3tri 4tetra 5penta 6hexa 7hepta 8octa 9nona 10deca First to name covalent compounds we need to know some Greek numerical prefixes. It'd be a good idea to memorize these since they will be useful in many other classes.

61. 1.P 2 O 5 a) phosphorus oxide b) phosphorus pentoxide c) diphosphorus pentoxide 2.Cl 2 O 7 a) dichlorine heptoxide b) dichlorine oxide c) chlorine heptoxide 3. Cl 2 a) chlorine b) dichlorine c) dichloride