1. The Building Blocks of Matter: Atoms- - - + + + + - - + + - - -

2. Matter Anything that has mass and takes up space (volume) Examples:
A brick has mass and takes up space
A desk has mass and takes up space
A pencil has mass and takes up space
Air has mass and takes up space
All of the above examples are considered matter because they have mass and take up space. Can you think of anything that would not be considered matter?

3. Atoms
Smallest possible unit into which matter can be divided, while still maintaining its properties.
Made up of:
protons
neutrons
electrons
The solar system is commonly used as an analogy to describe the structure of an atom - + - + + - + + - -
For example, what is the
smallest possible unit
into which a long essay can be
divided and still have some meaning?

4. What’s the Size of an Atom?
In order to try to gain an idea of how small an atom really is, you will complete the following activity.
Cut a strip of 11-inch wide paper in half.
Give one half to your partner.
Each of you cut your own piece in half, discard the other half.
Continue cutting and discarding the strips as many times as you can.
Make all cuts parallel to the first one.

5. Results
How many cuts were you able to make? How close do you think you came to the size of an atom? How many more cuts would you have to make?
31 cuts = the average size of an atom
4.5 x 10-9 inches ( )
41 cuts = the average size of a nucleus
4 x inches ( )
58 cuts = Quarks!
4 x inches ( )

6. Atoms are so small that…
it would take a stack of about 50,000 aluminum atoms to equal the thickness of a sheet of aluminum foil from your kitchen.
a human hair is about 1 million carbon atoms wide.
a typical human cell contains roughly 1 trillion atoms.
it would take you around 500 years to count the number of atoms in a grain of salt.
1 million carbon atoms = .
Just one of these grains

7. Sub-Atomic Particles Weight Comparison (protons, neutrons, electrons)
Neutron = x10-27 kg Proton = x10-27 kg Electron = x10-31 kg - - +
1839 electrons = 1 neutron
1836 electrons = 1 proton +
How do you think the mass of a neutron
compares to that of a proton?
1 neutron ≈ 1 proton

8. Sub-atomic Particles Size Comparison (protons, neutrons, electrons, & quarks)
Size in atoms
Size in meters (m)
Atom 1
10-10
Nucleus
__1__
10,000
10-14
Proton or Neutron
___1___
100,000
10-15
Electron or Quark
_____1____
100,000,000
10-18
(at largest) - - - + + + + - - + + - - -

9. + The Atom’s “Center” - - -
Protons and neutrons are grouped together to form the “center” or nucleus of an atom.
Notice that the electrons are not apart of the nucleus + - - -

10. What would be the atomic number of this atom?
The atomic number is the number of protons (+) in the nucleus of an atom -
What would be the atomic number of this atom? + - -

11. + Protons (+) Help make up the nucleus of the atom
Identify the atom (could be considered an atom’s DNA)
Always equal to the atomic number of the atom + - +

12. Electrons (-)
Found outside the nucleus of the atom, in the electron orbits/levels/shells;
Equal to the number of protons (until a reaction occurs)
Each orbit/level/shell can hold a maximum number of electrons
1st = 2,
2nd = 8,
3rd = 8 or 18, etc…)
Move so rapidly around the nucleus that they create an electron cloud + - -

13. + Mass Number + What would be the mass number of this atom? - - -
The total number of protons and neutrons in an atom’s nucleus
Expressed in Atomic Mass Units (amu)
Each proton or neutron has a mass of 1 amu
What would be the mass number of this atom? - +
 3
 4 + -
3 protons + 4 neutrons = a mass number of 7 amu
Why did we not account for the electrons when calculating the mass number? -

14. 1 Electron = 9.10938356 × 10-31 kilograms

15. Atomic Mass
The weighted average of the masses of all the naturally occurring isotopes of an element
The average considers the percent abundance of each isotope in nature
Found on the periodic table of elements
Example
What would be the atomic mass (≈) of Hydrogen if these three isotopes
were found in the following percentages (99.9, 0.015, 0) respectively? - + + + - -
Hydrogen (Protium)
Mass # = 1 amu
Hydrogen (Deuterium)
Mass # = 2 amu
Hydrogen (Tritium)
Mass # = 3 amu
If you simply average the three, 2 amu (1 amu + 2 amu + 3 amu/3) would be the atomic mass, but since 99.9% of the Hydrogen is Protium, the atomic mass is around 1 amu (.999 x 1 amu)

16. Atoms With The Same Number Of Protons Can Have Different Numbers of Neutrons

17. Neutrons Help make up the nucleus of the atom+ -
Help make up the nucleus of the atom
Vary in number of neutrons in different forms (isotopes) of an element. This is why the mass is a decimal number.

18. How Can We Know How Many of Each Particle in an Atom?

19. A=P&E M-A=N? Why Should We Care ?
# of PROTONS tells us the IDENTITY of an element
Arrangement of ELECTRONS tells us about an element’s REACTIVITY
Number of NEUTRONS tells us the MASS (+protons) and identifies ISOTOPES

20. A = P & E M - A = N How many protons? 1 How many electrons? 1
How many neutrons?

21. Hydrogen (H) Atom - Notice the one electron in the first orbital = 1 +
= 0 -
How many
more electrons
can fit in the 1st
orbital/ level? +
Even though there are no neutrons present,
Hydrogen is still considered an atom

22. Oxygen (O) Atom
Notice the two electrons in the first orbital/level and the six in the second + -
= 8
How many
more electrons
can fit in the 2nd
orbital/ level? - - - + + + + - - + + - - -

23. Sodium (Na) Atom
Notice the two electrons in the first orbital/level, eight in the second, and one in the third + -
= 11
= 12 - - -
How many
more electrons
can fit in the 3rd
orbital/ level? - + + + + - - - + + - - - -

24. Practice Building Atoms Together
Using the SCIENCE MATERIALS in your baggie, build the following atoms, and determine the atomic number and mass number for each.
Protons = mini-marshmallows
Neutrons = fruit loops
Electrons = mini M&Ms
Atoms
Protons
Neutrons
Electrons
Fluorine 9 10
Nitrogen 7
Oxygen 8
Sodium 11 12

25. Use Your Science Materials To Do The Atomic Structure Lab
= Protons
= Neutrons
= Electrons

26. Ion
Charged particle that typically results from a loss or gain of electrons
Two types:
Anion = negatively charged particle
Cation = positively charged particle - - - + -
= 8 + + + + - - 9 6 + + - -
Now that three electrons were lost, the number of electrons (6) and protons (8) is still unbalanced; therefore, it is still an ion, but now it is specifically referred to as a cation.
Now that this atom of oxygen just gained an electron, it is no longer neutral or an atom. It is now considered an ion (anion). This ion has more electrons (9) than protons (8).
Currently, this atom of oxygen is neutral because it has an equal number of electrons (8) and protons (8). - -
Symbol = O1-
Symbol = O2+
Symbol = O

27. Building Ions
Using the whiteboard and the proton, neutron, and electron pieces, build the following ions, and determine their atomic and mass numbers.
Ions
Protons
Neutrons
Electrons
Carbon (C³¯) 6 9
Hydrogen (H¹+) 1
Oxygen (O²¯) 8 10
Lithium (Li³+) 3 4
Sodium (Na¹¯) 11 12
Be aware that the atomic and mass numbers are not
impacted by the loss or gain of electrons.