1. Work silently. Raise hand to ask Ms. Hughes anything.
Do now
Work silently. Raise hand to ask Ms. Hughes anything.
Draw bohr model for K
Draw bohr model for C

2. Announcements Unit 3 test this Friday
If you have not taken 2 chemistry tests yet this semester, see me after to arrange a make up
Also, come in for quick tutoring, then RETAKE GLEs for a GRADE BOOST

3. Mystery Element When it reacts with Oxygen it is called rust.
Last year a movie came out called _ _ _ _man.
If you don’t have enough of this, you may have anemia.
Did it today because we didn’t have much time bc of the mentoes and coke. Did not like that.

4. Today!
Learn an easier way to draw atoms than Bohr Models.

5. Bohr Models of Atoms (1913)
Depict an atom as a small, positively charged nucleus surrounded by electrons that travel in circular energy levels (aka orbitals) around nucleus
16 p+
16 no
Sulfur: 16 protons
16 neutrons
16 electrons

6. Steps to Making a Bohr Model
Figure out how many protons, neutrons, and electrons are in the atom
Draw the nucleus (circle) with # p+ and # no inside
Draw the first energy level (circle around nucleus) and draw up to 2 dots (electrons)
If needed, draw second energy level (second circle) and draw up to 8 dots (electrons)
If needed, draw third energy level (third circle) and draw up to 18 dots (electrons)
If needed, draw fourth energy level (fourth circle) and draw up to 32 dots (electrons)
Continue drawing energy levels as needed (draw up to 32 dots on each)

7. Energy Levels Where the electrons live!!! Level 1: holds 2

8. Valence Electrons
Valence electrons: the electrons in the outside energy level -
ALL TOGETHER, SODIUM HAS 11 ELECTRONS.
How many valence electrons does sodium have? - - - - -
P=11 N=12 - - -
NUCLEUS - -

9. How many valence electrons in sodium?

10. How many valence electrons in neon?

11. How many valence electrons in boron?

12. How many valence electrons in carbon?

13. Lewis Dot Structures C
The chemical symbol goes in the middle
Represents the nucleus and inner energy levels
The valence electrons go on the outside
What do we notice about Carbon’s Lewis Dot Structure?

14. C - - - - - - P=6 N=6 The chemical symbol goes in the middle
Represents the nucleus and inner energy levels
The valence electrons go on the outside -

15. Electrons only pair up when they have to

16. C - - - - - - P=6 N=6 The chemical symbol goes in the middle
Represents the nucleus and inner energy levels
The valence electrons go on the outside -

17. I DO: Draw the Lewis Dot structure for fluorine

18. Draw the Lewis Dot structure for hydrogen

19. WE DO: Draw the Lewis Dot structure for helium

20. Electrons only pair up when they have to
Level 1 holds how many electrons??? 2
So, Helium’s dot structure has paired electrons because they have to

21. Draw the Lewis Dot structure for nitrogen

22. Draw the Lewis Dot structure for silicon

23. YOU DO: Draw the Lewis Dot structure for beryllium

24. Draw the Lewis Dot structure for carbon

25. Draw the Lewis Dot structure for oxygen

26. Draw the Lewis Dot structure for calcium

27. To Ms. H:
Lewis dot structures for elements with atomic number 1-18

28. The Rule What is “the rule” for valence electrons? There is a pattern
Can you find it???
Shhh, don’t say what it is
Let everyone get a chance to figure it out for themselves

29. Background for The Rule
Periodic table has columns
There are eight main columns (the tall ones)
Can we find the 8 tall columns?
We can assign numbers 1-8 to the eight tall columns

30. The Valence Electron Rule
For the 8 tall columns,
# of valence electrons = column #
!!!Wow!!!
Now for ALL elements in those 8 columns we know the # of valence electrons

31. Rapid Fire!!! Li Ca B N O Ar K Be S Al P

32. Exit Slip What are valence electrons?
What’s the rule for valence electrons?
Hw:
Draw Lewis Dot structures for Xe, Sr, Sb, I, Se, Rb, Ge, Ga
Top ten: how’d we do?