Name: _______________________________________________ Date: ______________________________ Period: _________
Unit 4 Test Study Guide
Part 1: History of the Atom
Sketch the atom models for the following scientists and summarize their experiments that led to their models.
Democritus
Dalton
Thomson
Rutherford
Bohr
Part 2: The Atom
Complete the following table.
Element
Symbol
Atomic #
Atomic Mass
# protons
# neutrons
# electrons
Nuclear
Symbol
Argon
Cd
59
207
184
W
74
Part 3: The Ion
Complete the following table.
Element
Ion
Symbol
Co2+
Atomic #
Atomic
Mass
# protons
13
46
Cs2+
Iodine (-1)
# neutrons
# electrons
10
44
Nuclear Symbol
(include charge)
59
Co2+
27
Part 4: The Isotope
Complete the following table.
Element
Hyphen Notation
Atomic #
Atomic Mass
# protons
# neutrons
# electrons
Nuclear
Symbol
23
Vanadium-52
Barium
139
209
Pb
82
62
47
Part 5: Weighted Average Atomic Mass
Solve the following problems + round your answer to the correct number of significant figures.
1. What is the average atomic mass of silicon given the following abundance information on the isotopes of
silicon?
Mass number
Abundance
Si-28
92.21 %
Si-29
4.70 %
Si-30
3.09 %
2. Calculate the atomic mass of potassium if the abundance atomic masses of the isotopes making up its naturally
occurring samples are as given below.
Isotope
potassium-39
potassium-41
Relative abundance Atomic Mass
93.12 %
38.964 amu
6.88
40.962 amu
3. What is the average atomic mass of hafnium given the following abundance information on its isotopes?
Mass number
Abundance
Hf-176
5%
Hf-177
19 %
Hf-178
27 %
Hf-179
14%
Hf-180
35%
4. Neon has two isotopes. There are 800 atoms of Neon (with an average atomic mass of 20.3405 amu). 70% of
the atoms are Neon-20 (19.8865 amu). What is the mass of the other Neon isotope? (Write it in hyphen
notation and nuclear).