Download The Atom - Exam #2 Review

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The Atom - Exam #2 Review
Atomic Model History – MAKE SURE YOU CAN MATCH EACH SCIENTIST TO HIS MODEL!!
1. Draw and name each scientist’s model of the atom:
a. Dalton
Billiard Ball Model
b. Thomson
Chocolate Chip Cookie Model
c. Rutherford
Peach Model
d. Bohr
Planetary Model
e. Chadwick
(has neutrons in nucleus)
f. Modern (Schrödinger and Heisenberg)
Quantum Mechanical Model
2. Who was the first to suggest that atoms could exist and gave them their name by calling them ATOMOS?
Democritus
3. Who was the scientist that proposed the first atomic theory?
John Dalton
4. List the 4 points of the first atomic aheory.




Atoms are indivisible particles (can’t be divided).
All atoms of one element are the same.
Atoms of different elements are different.
Different atoms combine to form compounds.
5. Who was the first to show that the atom was made up of even smaller particles? What particle did he
discover? J.J. Thomson – discovered electrons
6. Who discovered the nucleus? Protons? Neutrons?
Nucleus and Protons – Rutherford
Neutrons – Chadwick
7. What did Rutherford discover from his Gold Foil Experiment?
Atoms are mostly empty space and contain a dense, positive nucleus
Basic Atomic Structure
8. List the three subatomic particles and their charges.
Protons: positive (+)
Neutrons: neutral (0, no charge)
Electrons: negative (-)
9. List the 2 regions of the atom and what subatomic particles are found in each.
Nucleus – protons and neutrons
energy levels (electron cloud) – electrons
10. Why are atoms neutral?
Protons (+) = Electrons (-)
negative charge cancels out the positive charge
11. What is the name of the smallest unit of an element? Atom
12. What particle(s) make up the atomic number? Protons
13. What particle(s) make up the mass number? Protons + Neutrons
14. What is the importance of atomic numbers? Identifies the element!
15. Draw Bohr Models (on the back) for:
a. Lithium
2 valence e-
c. Calcium
P=3
N=4
Mass: 7
- 3 p+
4 n0
1 valence e-
Mass: 40
- 20 p+
20 n0
P=20
N=20
b. Nitrogen
P=7
N=7
Mass: 14
- 7 p+
7 n0
5 valence e-
d. Argon
Mass: 40
- 18 p+
22 n0
P=18
N=22
8 valence e-
Isotopes
16. What makes isotopes the same and what makes isotopes different?
SAME element (SAME # of protons)
DIFFERENT mass # (DIFFERENT # of neutrons)
17. How can you determine if the atom is the most common isotope?
Most common isotope = atomic mass from the Periodic Table rounded to a whole number
18. What is the difference between mass number and average atomic mass?
Mass # = mass of each specific isotope (protons + neutrons)
Average atomic mass = weighted average mass of ALL isotopes (found on the Periodic Table)
19. Write the following isotopes in nuclear notation:
14
a. Carbon – 14
6
b. Iron – 56
56
26
C
Fe
c. Atom that has 13 protons and 15 neutrons
28
13
Al
20. Element A has 8 protons and 7 neutrons and element B has 8 protons and 8 neutrons. Are these isotopes
or different elements? Why? Isotopes – they have the same # of protons, which means they are the
same element. Different # of neutrons only changes the mass #.
21. Find the average atomic mass for the following atoms:
a. 15%
55
Fe, 85%
0.15 x 55 =
56
Fe
8.25
0.85 x 56 = + 47.6
55.85 amu
b. 95% 14N, 3% 15N, 2%
0.95 x 14 = 13.3
0.03 x 15 =
16
N
0.45
0.02 x 16 = + 0.32
14.07 amu