Get out your element flash cards and quiz your neighbor for 5 minutes by hcj

VIEWS: 1 PAGES: 14

									Get out your element flash
cards and quiz your neighbor
for 5 minutes.
Element ID Quiz Tomorrow. Be ready for it.


Get out your homework from yesterday.
Review – Electron Energy Levels
   The atom contains energy levels (Bohr
    called them “shells”) .

   The first energy level holds 2 electrons.

   The second energy level holds 8 e-

   The third energy level holds 8 e-
Example:        Helium
   How many protons:          2

   How many neutrons:         2

   How many electrons:        2

 Electrons in 1st energy level:   2
 Electrons in 2nd energy level:   0
 Electrons in 3rd energy level:   0
Example:        Phosphorus
   How many protons:          15

   How many neutrons:         16

   How many electrons:        15

 Electrons in 1st energy level:    2
 Electrons in 2nd energy level:    8
 Electrons in 3rd energy level:    5
Electron Dot Diagram
   Looks only at the valence electrons.

   Dots represent electrons.

   Ex: Beryllium has 2 valence electrons




                     Be
Example:
Oxygen:
How many valence electrons:   6


              O
Example:
Sodium:
How many valence electrons:   1


              Na
Example:
Florine:
How many valence electrons:   7


               F
What do atoms want?
   A full outer shell.

   They can get this by getting electrons for
    giving them away.

   Ex: Nitrogen has 5 valence electrons.
    ◦ It can gain 3 to get a total of 8   or,
    ◦ It can lose 5 to drop to the lower level

       Which do you think is more likely?
Examples:
Aluminum:

How many valence electrons:       3

How many does it need to get:     5

How many can it give away:    3

              Al
Examples:
Argon:

How many valence electrons:       8

How many does it need to get:     0

How many can it give away:    8

              Ar
How do they bond?
   An atom that needs will get from an atom
    that gives.

   Chlorine needs 1 electron and Sodium is
    happy to give one up.


         Cl +        Na = Cl Na
How about water?
Get a whiteboard and lets practice.
Homework
Worksheet on Lewis Structures.

								
To top