1. 2017 SSNI Atomic Fundamentals Marissa Reigel
A discussion and activities about the building blocks of matter.

2. Matter Term that describes all of the physical substances around us
your table
your body
your pen or pencil
Everything!

3. Matter… Anything that Matter is made up of different kinds of atoms
has mass and
takes up space (has volume)
Matter is made up of different kinds of atoms

4. Matter… Includes all things that can be Does not include seen tasted
smelled
touched
Does not include
heat
sound
light

5. Activity: How big is an atom?
Materials
Sheet of paper
Scissors
Procedure
Cut paper in half
Discard half and cut remaining sheet
Repeat 90 times

6. Models Often used for things that are too small to be observed
large to be observed
difficult to be understood easily

7. Models…
In the case of atoms, scientists use large models to explain something that is very small
Models of the atom are used to explain data or facts that were gathered experimentally
Models are theories

8. Early Models of the Atom
Empedocles (490 BC)
Suggested there were four basic elements
Earth
Air
Fire
Water
Ratio of elements determined the substance
Stone was thought to contain a high amount of earth
Animals were thought to have a higher ratio of both water and fire

9. Early Models of the Atom…
Democritus (550 BC)
Proposed the universe was made of empty space and tiny bits of stuff called “atomos”
Atoms could not be divided
Reasoned, “All that exists are atoms and space. Everything else is opinion.”

10. Early Models of the Atom…
John Dalton
All elements are composed of indivisible particles (atoms)
Atoms of the same element are the same
Atoms of different elements are different
Compounds consisted of atoms of different elements combined together
Element A atom
Element B atom
Element C atom
Compound with
elements A, B, & C

11. Early Models of the Atom…
JJ Thomson
Plum pudding model
Atom is
Made of a positively charged material (pudding or soup)
With the negatively charged electrons scattered through it

12. Early Models of the Atom…
Ernst Rutherford
Mostly empty space
Small, positive nucleus
Contained protons
Negative electrons scattered around the outside

13. Early Models of the Atom…P E
Niles Bohr
Electrons move in definite orbits around the nucleus (like planets around the sun)
Nucleus (sun) is composed of protons and neutrons
Electrons (planets) orbit around the nucleus
Neutrons discovered by James Chadwick

14. Atomic Structure
Nucleus
Protons
Neutrons
Electrons
Space

15. Atomic Structure
If an atom could be enlarged to the size of a football stadium…
The nucleus (protons and neutrons) would be the size of a grape or a marble at midfield
Orbiting electrons would be size of salt grains swirling around the upper deck

16. Atomic Structure – Bohr’s model based on results of Gold Foil Experiment

17. Atomic Structure – Bohr’s model based on results of Gold Foil Experiment
(Zinc Sulphide)

18. Activity: What’s Inside the Atom?
Roll marble
Determine the geometric
shape underneath

19. Atomic Structure… Electrons
Tiny, very light particles (negligible mass)
Have a negative electrical charge (-)
Move around the outside of the nucleus

20. Atomic Structure… Protons Number of protons = atomic number
Much larger and heavier than electrons
Have a mass of 1 AMU
Protons have a positive charge (+)
Located in the nucleus of the atom
Atoms with same number of protons are the same element
Number of protons = atomic number

21. Atomic Structure… Neutrons
Large and heavy like protons
Have a mass of 1 AMU
Neutrons have no electrical charge
Located in the nucleus of the atom
Neutralize repulsive force of positive protons
Acts as a “glue” that keeps protons in the nucleus
Number of protons + number of neutrons = atomic mass

22. Isotopes Atoms that have Have the same atomic number
Have different atomic mass numbers
Same number of protons
Different number of neutrons

23. Isotopes…

24. Atomic Structure Recap

25. Describing Atoms Atomic Number is the number of protons
In a stable atom, the number of protons equals the number of electrons
Atomic Mass Number
Number of protons and neutrons
Atomic Weight
Average mass of the naturally occurring isotopes of an element

26. Pop Quiz! Which atoms are the same element? What is the mass of…
Atom A has 65 protons, 65 neutrons, and 65 electrons
Atom B has 65 protons, 66 neutrons, and 65 electrons
Atom C has 66 protons, 65 neutrons, and 65 electrons
Atom D has 65 protons, 65 neutrons, and 66 electrons
What is the mass of…
Atom A?
Atom B?
Atom C?
Atom D?

27. Atoms A, B, and D are the same element
Pop Quiz Answers
Which atoms are the same element?
Atom A has 65 protons, 65 neutrons, and 65 electrons
Atom B has 65 protons, 66 neutrons, and 65 electrons
Atom C has 66 protons, 65 neutrons, and 65 electrons
Atom D has 65 protons, 65 neutrons, and 66 electrons
Atoms A, B, and D are the same element
What is the mass of…
Atom A? 130 amu
Atom B? 131 amu
Atom C? 131 amu
Atom D? 130 amu

28. Periodic Table of the Elements

29. - + Ions… An atom that carries an electrical charge
If a neutral atom gains an electron, the atom becomes negatively charged
Because it has more negative charges than positive charges + -

30. - + Ions… An atom that carries an electrical charge
If a neutral atom loses an electron, the atom becomes positively charged
Because it has more positive charges than negative charges - +

31. Ions… Have either The number of protons does not change in an ion
More protons than electrons (positive charge)
More electrons than protons (negative charge)
The number of protons does not change in an ion
The number of neutrons does not change in an ion
So, both the atomic number and the atomic mass remain the same

32. Ions… This atom has lost an electron This atom has gained an electron
Now it has one more proton than electron
One more proton means one more positive charge
This makes the total charge of the atom POSITIVE
This atom has gained an electron
Now it has one less proton than electron
One less proton means one less positive charge
This makes the total charge of the atom NEGATIVE

33. Pop Quiz! What is the overall charge of an atom that has
50 protons , 51 neutrons, and 50 electrons?
50 protons , 51 neutrons, and 49 electrons?
50 protons , 51 neutrons, and 51 electrons?

34. Pop Quiz Answers What is the overall charge of an atom that has
50 protons , 51 neutrons, and 50 electrons? Neutral
50 protons , 51 neutrons, and 49 electrons? +1
50 protons , 51 neutrons, and 51 electrons? -1

35. Review Matter is comprised of atoms
Atoms are comprised of three types of particles
Protons
Neutrons
Electrons
Define an element
Located in the nucleus
Have a positive charge
Have a mass of 1 amu
Neutrons
Located in the nucleus
Have no charge
Neutralize protons repulsive force
Have a mass of 1 amu
Electrons
Orbit the nucleus
Have a negative charge
Have a negligible mass
Isotopes
Same number of protons
Different number of neutrons

36. Final Exam – Fill in the table
Complete the table.
Which atoms are the same element?
Atom
Protons
Neutrons
Electrons
Charge
Mass A 80 79 B -1
165 C 90 95 D
180 E
100 +2 F -2
200 G
110
112
220

37. Final Exam Answers Complete the table.
Which atoms are the same element?
A and B / C and D / E and F
Atom
Protons
Neutrons
Electrons
Charge
Mass A 80 79 +1
160 B 85 81 -1
165 C 90 95
185 D
180 E
100 93 +2
195 F
105 97 -2
200 G
110
112
220