Mr. Sheehan’s Pd
Name:
Chem Extra Chp 4 Practice
1. Summarize the FOUR parts of Dalton’s Atomic Theory.
Hints: Made of..., same...., combine...., chemical reactions.
a.
b.
c.
d.
2. The atomic number shows the # of ______________, which equals the number of _____________.
3. Written as an equation, what does the mass number show?
4. Fill in the rest of the table using the information provided. Do not use a periodic table.
Atomic
symbol
Atomic
number
Atomic
mass
B
Na
Ga
Y
Cu
Tc
Yb
Ac
Tl
Fm
Sg
5
11
11
24
Protons
Neutrons
Electrons
5
6
5
31
37
89
39
29
35
100
43
102
81
100
225
206
89
106
159
159
70
Mr. Sheehan’s Pd
Name:
5. Fill in the table given the element. Round the atomic mass to the nearest whole number.
Atomic
symbol
Atomic
Mass
Neutrons
Protons Electrons
number
Number
6. Find the average atomic mass of the problems below:
***How do you find average atomic mass?
a. The relative abundance and atomic masses of copper isotopes are 69.2% for mass = 62.93 amu, and
30.8% for mass = 64.93 amu. Calculate the average atomic mass of copper.
b. Calculate the atomic mass of bromine. The two isotopes of bromine have atomic masses and
relative abundance of 78.92 amu (50.69%) and 80.92 amu (49.31%)
c. Neon has two isotopes. Neon with 19.992 amu is 90.00% abundant and the mass of 21.99 amu is
10.00% abundant. Calculate the average atomic mass of neon.
d. What is the atomic mass of silicon if 92.21% of its atoms have mass 27.977 amu, 4.70% have mass
28.976, and 3.09% have mass 29.974 amu?