1. Atomic History and Atomic Structure
8th Grade Science

2. Do Now Monday October 17th
Classify each element as a metal, nonmetal, or metalloid.
Arsenic (As)
Xenon (Xe)
Aluminum (Al)
An element that is malleable, ductile, and a good conductor of heat and electricity
An element that is a a dull solid that is brittle
An element that is shiny and is a semi-conductor.

3. TODAY’S PLAN TODAY’S DO
Identify 6 scientists who contributed to our knowledge of the structure of the atom.
Explain the structure of the atom.
Differentiate between the subatomic particles of an atom: protons, neutrons, and electrons;
TODAY’S DO
Complete a WebQuest about Atomic History and Atomic Scientists (Independently and Quietly)

4. Do Now Tuesday October 18th
What are the properties of metals?
What are the properties of metalloids?
What are the properties of nonmetals?

5. TODAY’S PLAN TODAY’S DO
Identify 6 scientists who contributed to our knowledge of the structure of the atom.
Explain the structure of the atom.
Differentiate between the subatomic particles of an atom: protons, neutrons, and electrons.
Discuss what the atomic number represents concerning the atoms of an element.
Discuss what the mass number represents concerning the atoms of an element.
TODAY’S DO
Quiz
Briefly review scientists and atomic structure
Calculate the number of protons, neutrons, and electrons in atoms of an element.

6. Atomic Theory
Changes over time…

7. Atomic Theory
Because we can not see atoms, we use models to teach and learn about atoms.
The atomic theory has changed over time as new technologies have become available.
Remember: Scientific knowledge builds on past research and experimentation.

8. On Page 40
Make a list of these names. Skip a line or two between each one so you can write a brief statement about each.
Democritus
Dalton
JJ Thomson
Rutherford
Bohr
Schrodinger

9. Atomic Theory Timeline
Scientist
Information
Model
Democritus
(400 BC)
Named atoms “atomos”
Said everything is composed of atoms.
Atoms are indestructible.
Between atoms lies empty space.
There is an infinite number and kinds of atoms.

10. Atomic Theory Timeline
Scientist
Information
Model
John Dalton (2000 years after Democritus)
All matter is made of atoms.
Atoms are too small to see, indivisible and indestructible.
All atoms of a given element are identical.

11. Atomic Theory Timeline
Scientist
Information
Model
J.J. Thomson
Discovered the negative electron, using the cathode ray tube
Plum Pudding model

12. Atomic Theory Timeline
Scientist
Information
Model
Ernest Rutherford
Atoms are mostly empty space
Discovered tiny, positively charged NUCLEUS using the gold-foil experiment
Name positive charged particle “proton”

13. Atomic Theory Timeline
Scientist
Information
Model
Neils Bohr
Concluded that electrons are located in neat planet-like orbits around the nucleus in certain energy levels

14. Scientist
Information
Model
Schrodinger (and many others):
Modern Atomic Theory
Electrons do not orbit the nucleus in neat planet-like orbits but move at high speeds in an electron cloud around the nucleus.
We can not know the exact location of an electron.

15. Rings (energy levels) outside nucleus
Atomic Structure
Copy this table into your journal.
Subatomic Particle
Mass (amu)
Charge
Location
Proton (p+) 1 +1
nucleus
Neutron (no)
Electron (e-) -1
Rings (energy levels) outside nucleus

16. Atomic Structure

17. Atomic Number and Mass Number
Identifies the element
Is the number of protons
In a neutral atom, is also
the number of electrons
Mass Number
Decimal number rounded to nearest whole number
Includes both protons and neutrons
Mass number = p+ + no
So, no = mass number – p+
Mass number when rounded

18. Calculating protons, neutrons, electrons
p+ = atomic # = 1
e- = p+ = 1
no = mass # - atomic # = 1-1 = 0

19. Calculating protons, neutrons, electrons
p+ = atomic # = 2
e- = p+ = 2
no = mass # - atomic # = 4-2 = 2

20. Calculating protons, neutrons, electrons
p+ = atomic # = 3
e- = p+ = 3
no = mass # - atomic # = 7-3 = 4

21. Do Now Wednesday October 18th
Answer the questions on the sheet given to you.
Blood Types of 100 Donors

22. TODAY’S DO TODAY’S PLAN
Determine the electronic structure for elements 1-20 on the Periodic Table.
TODAY’S DO
Check Homework
Review calculating the number of protons, neutrons, and electrons.
Draw the electronic structure of elements.

23. Element
Symbol p+ e- n0
1st energy level
2nd energy level
3rd energy level
4th energy level
Hydrogen
Helium
Lithium
Beryllium
Carbon
Nitrogen
Oxygen
Fluorine
Sodium

24. Element
Symbol p+ e- n0
1st energy level
2nd energy level
3rd energy level
4th energy level
Magnesium
Aluminum
Silicon
Phosphorus
Chlorine
Argon
Potassium
Calcium

25. Electronic Structure E1 = 2 electrons E2 = 8 electrons

26. Electronic Structure Example

27. Electronic Structure Example

28. Electronic Structure example

29. Do Now Friday October 20th
TURN IN YOUR HOMEWORK SHEET FROM WEDNESDAY IN THE BLACK BASKET.
Pick up from the front table and answer the questions on the sheet given to you.
Once you have finished, raise your hand so I can check your work.
Only when you have shown me that you know how to do the work will you be allowed to construct your model of an atom.

30. TODAY’S DO TODAY’S PLAN Explain the structure of the atom.
Discuss what the atomic number represents concerning the atoms of an element.
Discuss what the mass number represents concerning the atoms of an element.
Determine the electronic structure for elements 1-20 on the Periodic Table.
TODAY’S DO
Create Bohr Model of an atom of an assigned element

31. Do Now Tuesday October 25th
Draw and complete the table.
Atomic Symbol
Atomic Number
Protons
Neutrons
Electrons
Mass Number Al 6
Draw the electronic structure for Al.

32. TODAY’S DO TODAY’S PLAN Create a Bohr Model of an atom.
Discuss what the atomic number represents concerning the atoms of an element.
Discuss what the mass number represents concerning the atoms of an element.
TODAY’S DO
Create/Finish your Bohr Model of an atom of an assigned element
When finished with your atom model, pick up a puzzle sheet from the table in the front of the room and practice calculating protons, neutrons, and electrons for elements.
Color your sheet (with pencil) as directed to solve the puzzle.
Calculating p+, n0, e- QUIZ TOMORROW, Wednesday, October 26th!!

33. Bohr Atomic model
Beads: electrons, protons, and neutrons (3 different colors)
Pipe cleaners: energy levels
Make a nucleus by stringing the correct number and color of beads onto 1 pipe cleaner. The smash it into a little ball.
Make the appropriate number of energy levels by using 1 (for smaller energy levels) or 2 (larger energy levels) pipe cleaners with the correct color and number of beads for each energy level.
Connect the nucleus and each energy level by attaching strings between each so that all can spin freely. (Nucleus and energy levels should not touch.)
Attach the card for your element to the bottom of your model and hang from a cabinet or the line in the back of the room.