1. Atomic Structure

2. Unit Questions What are all things made of?
What is the structure of an atom and how was it discovered?
What makes one element different from the next?
How are atoms combined to make all substances on earth?

3. What are all things made of?
All things on Earth and in the Universe are made of atoms of elements
Atoms are the smallest particles or units of matter, that keep the identity of the substance.
An element is a substance that is made entirely from one type of atom

4. What are all things made of?
Example: Gold
If you keep breaking down gold, into smaller and smaller chunks you would get atoms of gold

5. What is the structure of an atom and how was it discovered?
Atoms of elements are made up of three things:
Protons
Neutrons
Electrons

6. What is the structure of an atom and how was it discovered?
Atoms have 2 areas that hold those sub-atomic (smaller than the atom) particles
Nucleus: the center of the atom that contains most of the mass of the atom.
This area holds the Protons and Neutrons
Electron cloud: surrounds the nucleus & takes up most of the space of the atom.
This area holds the electrons

7. What is the structure of an atom and how was it discovered?
The two locations:
Electron Cloud
Nucleus

8. What’s in the Nucleus? In the nucleus we find:
Protons: positively charged subatomic particles
Neutrons: neutrally charged subatomic particles

9. What’s in the Electron Cloud?
In the electron cloud we find:
Electrons: the subatomic particle with a negative charge and relatively no mass

10. What do you notice about the protons and electrons in this atom of carbon?

11. - + Subatomic Particles Particle Charge Mass (g) Location Electron
(almost no mass)
Electron cloud
Proton (p+) +
1 amu
Nucleus
Neutron
(no)
No charge

12. How do we know so much about atoms or elements if we can’t see them??

13. Atomic Theory
Our knowledge of the atom has changed over time as we increase our technology and understanding.

14. 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.

15. Atomic Theory Timeline
Scientist
Information
Model
John Dalton
All matter is made of atoms. Atoms are too small to see, indivisible and indestructible. All atoms of a given element are identical.

16. Atomic Theory Timeline
Scientist
Information
Model
J.J Thompson
Discovered the negative electron, and predicted that there also must be a positive particle to hold the electrons in place.

17. Atomic Theory Timeline
Scientist
Information
Model
Ernest Rutherford
Discovered the nucleus of an atom and named the positive particles in the nucleus “protons”. Concluded that electrons are scattered in empty space around the nucleus.

18. Atomic Theory Timeline
Scientist
Information
Model
James Chadwick
Discovered that neutrons were also located in the nucleus of an atoms and that they contain no charge.
Neutrons

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

20. Scientist Information Model
(Many Scientists!)
The 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.

21.
Additional video resource:

22. Think-Pair-Share!
Take a minute to read the essential question as I read it aloud: “How and why has the Atomic Theory changed over time?” After you have jotted down your notes in the space on your guided notes, exchange your thoughts with your partner. We will have share-outs and discuss the answer.

23. What makes one element different from the next?
The number of Protons determines which element the atom is!
The protons are like an atom’s fingerprint and tells the atom which element it is.
Example: All atoms with 6 protons in the nucleus are the element Carbon!

24. How do we know how many protons are in an element?
The Periodic Table of Elements tells us!

25. Periodic Table
Look at the periodic table given and look for the Element Carbon. Its symbol on the periodic table is C
What numbers are around Carbon?
What do you think these numbers tell us?

27. How do we know how many protons are in an element?
The Atomic Number: Tells us the number of Protons in each element.

28. How do we know the number of electrons in an atom?
Because every element has to have the same number of Protons and Electrons…
The Atomic Number also tells us the number of electrons an element’s atom has!

29. How do we know the number of neutrons in an atom?
The Atomic Mass # tells us the mass of the nucleus.
The two things found in the nucleus are the protons and the neutrons.
If we already know the number of protons we can use this to figure out the neutrons!

30. How do we know the number of neutrons in an atom?
If Carbon has an atomic mass of 12 that means that there are 12 particles in the nucleus.
We know using the atomic number that there are 6 protons.
So if we subtract the mass-atomic number we will get the number of neutrons!

31. Examples 1 2 Protons __ Protons ___ Neutrons __ Neutrons ___
1 2
Protons __ Protons ___
Neutrons __ Neutrons ___
Electrons___ Electrons ___

32. Atomic Math Practice
We will do an example together as a class then you will practice the rest on your own tonight for homework!
End of Notes Day 1

33. How are atoms combined to make all substances on earth?
In order to see how atoms of elements can combine we must first know:
How do we draw a model of an atom?
What rules to all atoms follow?
What are the ways atoms can combine based on the rules?

34. How do we draw an atom?
When atoms combine, they only combine the electrons. So we don’t need to draw everything in the nucleus.
How do we know how many electrons can fit on each ring around the nucleus?
The Rule of Eights!!!!!

35. How do we draw an atom? Rule of 8’s
All of the protons and the neutrons
The 3rd ring an hold up to 8 e-
The 1st ring can hold up to 2 e-
The 2nd ring can hold up to 8 e- 35

36. What does carbon look like?
Mass # = 12 atomic # = 6
p+ = 6 no = 6 e- = 6
6 p and 6 n live in the nucleus 36

37. Practice Drawing Atoms
Draw Lithium Draw Neon
Draw Sodium Draw Fluorine

38. How do atoms of elements combine?
All elements want to have full electron rings or orbits… if they don’t they will join with other atoms to make a compound!

39. How do atoms of elements combine?
Ionic Bonds:
when an element only has 1 or 7 electrons on it’s outer ring/orbit it will STEAL another atoms electron!
Example
The charge created holds together the elements…

40. How do atoms of elements combine?
Covalent Bond
When an element has 2-6 electrons on it’s outer ring/orbit it will SHARE electrons with other atoms
Example:
The movement of electrons holds the bond together.

41. Acting Out the Bonds!
I will demonstrate how bonds are created and what holds the atoms of each element together when they combine!