1. Elements Atoms and Nuclear
Discovery of Atom & Atom Structure
Periodic table and trends
Electrons
Isotopes and Nuclear Decay
Fission and Fusion

2. Elements Look for these: Here’s the BIG Picture Topic When
The Good Stuff
Homework
Discovery & Atom
Class 1
Building an atom
Proof of electrons
Organizing the Elements
Crash Course Chem ∞
Dissecting the PT ∞
Read pp , do Odds
Periodic Trends
Class 2
Electron Arrangements
Class 3
Reinforcement
Small Scale Lab/Other
Look for these:
Most Important
Real World Evidence

3. Electron Clouds

4. Electrons The next topic we will cover deals with electrons primarily.
[Name 5-10 facts you recall about electrons.]

5. Understanding electrons will allow you to understand….
Why chemical reactions occur
Why some atoms prefer to become ions, while others remain atoms.
Why some elements are reactive while others are not.
Specifically, it is important to know…
how many electrons are in an atom and where they are located

6. Electron Configuration
An atom’s electron configuration…
Describes the location of electrons within the atom
Will identify the shape of the electron clouds that the electrons form as they move.
Will use numbers and letters to describe an electron’s location and its cloud.

7. 1s2 An example The “s” tells you the electron’s cloud shape.
In this case it’s a spherically shaped cloud. It is called the s sublevel.
1s2
The “2” simply tells you how many electrons are in this cloud.
The “1” tells you how far from the nucleus the electrons are.
In this case 2 electrons are creating the cloud.
In this case, its in the 1st energy level, which is closest level to the nucleus.
Note: Each orbital can only hold 2 electrons. They must have opposite spins.

8. In summary…
1s2
Represents 2 electrons forming a spherical cloud that is in an energy level closest to the nucleus.

9. Electrons
Orb. Diag. E- Configuration H ____ He ____ Li ____ ____ Be ____ ____

10. B ___ ___ ___ ___ ___ C ___ ___ ___ ___ ___ O ___ ___ ___ ___ ___ Ne ___ ___ ___ ___ ___ Mg ___ ___ ___ ___ ___ ___

11. A new view of the atom
This was the old way…

12. 3s2 2s2 1s2 2py2 This is a more accurate model. 3pz2 2pz2 3px2 2px2
Nucleus
3pz2
2s2
2pz2
1s2
3px2
2px2
2py2
3py2
This is a more accurate model.

13. Another view of this model…
Here’s a better 3D representation

14. These all overlap
within the 2nd
energy level.
1s2
2s2
2px2
2py2
2pz2

15. The basics of stability
As electrons move around an atom, they shift its orientation about.
This electron movement makes the atom tend to toss and turn.
Atoms with “high energy” toss and turn more than those with low energy.
If the placement of electrons is more uniform…
the flipping about is minimized and the atom has lower energy/less movement. IT IS MORE STABLE!

16. Electron Placement and Stability.
3pz2
2s2
1s2
2pz2
3px2
2px2
2py2

17. Maximum Stability There are various levels of stability
However, maximum stability occurs when…
An atom has a completely filled outermost energy level
Stable ions will have electron configurations identical to one of the noble gases

18. Practice with Electron Configurations
Hydrogen He
Lithium
Beryllium
Boron
Carbon

19. Practice with Electron Configurations
nitrogen
oxygen
fluorine
neon
sodium
magnesium

20. Bellwork: Date:
Write the electron configuration and orbital diagrams for the following elements.
lithium
nitrogen
magnesium
carbon

21. Two important questions…
How many electrons are in the outermost energy level (the one farthest from the nucleus)?
How many unpaired electrons are there within the atom?

22. Combining the 3p orbitals
The 3px2, 3py2, and 3pz2 orbitals will now be put together as 3p6.

23. All the way through 1s2 2p6 2s2 3s2 3p6 4s2 *3d10 4p6 5s2 4d10 5p6
In this class, the furthest we will go is the element xenon (Xe).
As we do this one, you will learn a new orbital shape known as the d orbital.
It will have 5 clouds, each with 2 electrons (10 total electrons)
1s2
2p6
2s2
3s2
3p6
4s2
*3d10
4p6
5s2
4d10
5p6

24. Lewis electron dot structure
The X shown below could be the symbol for any element.
Only the outermost electrons will be shown in a Lewis diagram. Why?
This is the pattern to show where electrons are 1 2 X 5 3 8 6 4 7

25. Bellwork: date: [1) Selenium 2) Chromium]
a) Write the electron configuration. Include
orbital diagrams above configuration.
b) How many outermost electrons are there?
c) How many unpaired electrons are there?
d) How will it become stable? (gain/ lose+ number)
e) What will the symbol of the stable ion be?
f) Draw the Lewis electron dot structure for
the atom.

26. Mini-quiz e- configurations
1) Phosphorus 2) Potassium 3) Bromine
a) Write the electron configuration. Include
orbital diagrams above configuration.
b) How many outermost electrons are there?
c) How many unpaired electrons are there?
d) How will it become stable? (gain/ lose+ number)
e) What will the symbol of the stable ion be?
f) Draw the Lewis electron dot structure for
the atom.

27. Mini quiz 1) Phosphorus 2) Potassium 3) Iron 4) Bromine
a) Write the electron configuration
b) Include orbital diagrams.
c) How many outermost electrons are there?
d) How many unpaired electrons are there?
e) How will it become stable? (gain/ lose+ number)
f) What will the symbol of the stable ion be?

28. Shorthand Electron Configurations
This is a shorter way to do e- configurations
Steps…
1) Start with the nearest noble gas before the element you are doing.
2) Starting with that noble gas (put the noble gas in [brackets], finish the electron configurations

29. Bellwork: Date: [1) rubidium) 2) sulfur 3) magnesium 4) arsenic]
a) Write the SHORTHAND electron configurations
b) Include orbital diagrams.
c) How many outermost electrons are there?
d) How many unpaired electrons are there?
e) How will it become stable? (gain/ lose+ number)
f) What will the symbol of the stable ion be?

30. Backup