Download Name: Period:______ Date: CHEMISTRY Chapter 3 AND Nuclear

Name:_____________________________________ Period:_________ Date:______________
CHEMISTRY Chapter 3 AND Nuclear Chem Review Worksheet
Directions: Put the number of the definition below into the square with the appropriate term. Check your answers by
adding the numbers to see if all the sums of all rows and columns add up to the same number, the Magic Number. Not all
of the definitions will be used!
Democritus
Dalton
Thomson
Average atomic
mass
Total
Rutherford
Neutron
Nucleus
Beta Particle
Total
Isotope
Heisenberg and
Schrodinger
Mass Number
Electrostatic
Force
Total
Electron
Law of Multiple
Proportions
Strong Force
Fission
Total
Bohr
Alpha Particle
Law of Definite
Proportions
Fusion
Total
Total
Total
Total
Total
Magic Number:___________________
1. Made a mental model of the atom by thinking about repeatedly cutting a piece of gold in half until he
reached a basic particle that could no longer be cut in half and still be gold; he called the smallest
particle atomos; Greek philosopher.
2. The positive particle in the nucleus of an atom.
3. The dense, tiny, positively charged core of an atom; contains protons and neutrons.
4. Proposed an atomic theory consisting of 5 points that explained the law of conservation of mass, the law
of definite proportions, and the law of multiple proportions.
5. Combining to atoms together to make a larger atom. The sun does this.
6. Discovered the nucleus using his gold foil experiment.
7. Discovered the charge of the electron
8. The weighted average of the atomic masses of the naturally occurring isotopes of an element.
9. The smallest particle of an element that still retains the chemical properties of that element.
10. Atoms of the same element that have different masses.
11. The repulsive force in the nucleus
12. Losing 2 protons and 2 neutrons to become more stable.
13. Mass of protons and neutrons.
14. The number of protons in the nucleus of each atom of an element.
15. The negative particle that circles the nucleus.
16. The neutral particle in the nucleus of an atom.
17. Believed that the earth was made up of 4 elements, water, fire, earth, and air.
18. Proposed the “plum pudding” model of the atom; discovered the electron.
19. converting a neutron into a proton and emitting an electron
20. splitting a large atom into smaller atoms
21. A bucket of water, a pool filled with water, and an ocean filled with water all have water as a ratio of
one oxygen atom to two hydrogen atoms.
22. If the mass of the reactant is equal to the mass of the product what law is being demonstrated?
23. combining two smaller atoms together into a larger atom
24. the attractive force in the nucleus
25. Thought electrons are in rings around the nucleus
26. Created the modern model of the atom where electrons are in clouds.
27. When chemical reactions take place atoms rearrange in whole number ratios. Atoms do not split in half
for chemical reactions.
Ch. 3 Review Questions:
1. Explain each of the following in terms of Dalton’s atomic theory:
a. The law of conservation of mass
b. The law of definite proportions
c. The law of multiple proportions
Potential long answer question on the test. Explain how the model of the atom changed over time.
a. Thomson did the cathode ray tube experiment. What did he find and what model of the atom did he
develop. Include a drawing.
b. Rutherford did the gold foil experiment. What did he find? How did that change the model of the atom?
Draw the new model.
c. Bohr had ideas of how the structure of the electrons. What did he propose? Draw his model of the atom.
d. Schrodinger and Heisenberg used the information that an electron acts as a wave. How did this change
the model of the atom? Draw the new model of the atom.
2. Complete the following table describing properties of subatomic particles:
Particle
Location in atom
Relative electric
charge
Mass Number
Relative mass
(amu)
3. Define the terms below, describe how you would find them (on the periodic table, by using a formula,
etc…)
a. Atomic number
b. Mass number
c. Average atomic mass
4. Neutral atoms will always contain the same numbers of: ________ and ________
5. Which subatomic particle determines the identity of an element? ______________________
6. Why is the mass number a whole number, but the atomic mass on the periodic table is not?
7. What makes two isotopes of an atom different from each other? (name 2 things) What will those two isotopes have in
common? (name 1 thing)
8. If you add one proton to a nitrogen atom, how would it change?
9. Identify the most common isotope amongst the pairs below, and EXPLAIN your reasoning:
a. Neon-20
or
Neon-22
b. Copper-63
or
Copper-65
10. If you know only the following information can you always determine what the element is? (Yes or No):
a. Number of protons _________
b. Number of neutrons_________
c. Number of electrons in a neutral atom_____________
d. Number of electrons_________
11. Complete the following table
Isotope name
Isotope symbol
# of protons
# of neutrons
# of electrons
24
20
Silver - 108
56
80
28
30
Tin-120
52
24
Cr
Iodine-127
Magnesium-26
79
35
Br
12. What is the average atomic mass of hafnium if, out of every 100 atoms, 5 have a mass of 176 amu, 19 have
a mass of 177 amu, 27 have a mass of 178 amu, 14 have a mass of 179 amu, and 35 have a mass of
180.0amu? Give your answer to 2 decimal places.
13. Calculate the average atomic mass of magnesium, using the following data. Give your answer to 3 decimal places.
Isotope
mass(amu)
relative abundance (%)
Mg-24
23.985
78.70
Mg-25
24.986
10.13
Mg-26
25.983
11.17
14. Lithium has two naturally occurring isotopes: lithium-6 and lithium-7. If the average atomic mass of lithium is 6.941
amu, which isotope is the most abundant? Explain how you know.
Nuclear Chemistry Review Problems:
15. Write the nuclear equation for the beta decay of cerium-141:
16. Write the nuclear equation for the alpha decay of platinum-191.
17. Write the isotope symbol for the following elements:
a. An atom with 16 protons and 16 neutrons
b. An atom of nickel with a mass of 60
18. Predict whether the following combinations of protons and neutrons would be stable. If stable, write the symbol
of the isotope. If unstable, write “unstable”
a. 15 protons, 25 neutrons ___________________________
b. 28 protons, 32 neutrons ___________________________
c. Describe two ways which an isotope can be unstable
19. List three possible elements which could have 40 neutrons:
20. Describe what happens to the neutron to proton ratio as the atomic number increases. Use two different elements
as examples to support your statement:
21. Describe the two forces at work in the nucleus:
22. Fill in the blanks for the following nuclear reactions.
a. ______ 
256
b. 103 Lr 
187
76
4
2
Os  10 e
He + _______
23.
Write equations for the following types of nuclear decay:
a. Sodium-24 undergoes beta decay
b. Platinum-175 undergoes alpha decay
24. Explain what it means for an atom to be radioactive.
25. What is happening to a radioactive element at the half life?
26. How is knowing the half-life helpful?
27. If you have 20 grams of a radioactive sample that has a half-life of 250 years, how much will be left in
750 years?
28. Assume the half-life for a particular substance is 50 years. If you start with 400.0 grams of this
substance, how long will it take so that only 6.25 grams of the original sample remains?
29. How much of the sample was at the start if the half-life of the substance is 3 days and 27 days have gone
by and there is 5 g of the sample left?
30. Potential long answer question on the test. Describe the difference between fission and fusion. And
Explain three positive outcomes and three negative outcomes of fission and fusion reactions.