Name ______________________________
Period _____
Date _______________
CHEMISTRY I
ATOMIC STRUCTURE REVIEW
PART I: Scientists
Match the following scientist to the correct contribution.
A. Dalton
B. Thomson
C. Bohr
D. Rutherford E. Aristotle
F. Democritus
_____1. used gold foil experiment to determine that most of the atom is empty space
and that there was a small, dense core inside the atom
_____2. developed the atomic theory:
_____3. experimented with cathode ray tube and discovered the electron and
_____4. proposed a general theory that the world was made of empty space and small, indivisible
particles called atomos; not based on experimentation
_____5. originated the idea that electrons travel in definite energy levels around the nucleus
_____6. matter was made of hyle, not atoms.
Atomic Theory (Postulates)
1.
All elements are composed of _____________________ particles called
___________________________.
2.
Atoms of the same element are _________________________. The atoms of any one element
are _________________________ from those of another.
3.
Atoms of different elements mix or combine in whole number
_____________________________.
4.
Chemical reactions occur when atoms ___________________, join, or
_______________________________.
In a chemical reaction, atoms of one element NEVER ___________________ into another.
PART II: Subatomic Particles
Complete the following chart.
Particle
Symbol
Charge
Relative Mass
Location
Proton
Neutron
Electron
PART III: Atomic Structure
Fill in the blanks.
1. ATOMIC NUMBER = __________________ = ___________________
2. MASS NUMBER = _____________________ + ____________________
3. NUMBER OF NEUTRONS = ___________________ - __________________
4. Complete the following chart.
Element
Protons
** Boron
Neutrons
6
70
** Carbon
**
Electrons
5
50
Mass Number
12
20
19
12
21
39
14
5. Write nuclear symbols for all of the elements in the chart above.
6. Define an isotope.
7. How are carbon-12 and carbon-14 similar? How are they different?
7. Draw Bohr models of those marked **.
8. Complete the following table.
Element
Symbol At. number
Protons
Neutrons
oxygen-16
8
oxygen-17
8
9
oxygen-18
8
nitrogen-15
8
Ne
beryllium-9
4
Average Atomic Mass
Electrons
Mass number
16
18
20
1. What is the atomic mass of silicon if 92.21% of its atoms have a mass of 27.977 amu, 4.70% have
a mass of 28.976 amu, and 3.09% have a mass of 29.974 amu? (28.09 amu)
2. Calculate the average atomic mass of chromium, given the percent abundance and mass of each
isotope: 4.350 % at 49.946 amu; 83.790% at 51.941 amu; 9.500% at 52.941 amu; and 2.360% at
53.939 amu. (52.00 amu)
3. Precise atomic masses of each isotope of magnesium are given below, along with the fractional
abundance of each isotope. Calculate the average atomic mass. (24.31 amu)
isotope
Mg-24
Mg-25
Mg-26
mass (amu)
23.98504
24.98584
25.98259
Percent abundance
78.70 %
10.13 %
11.17 %