ESCS Unit 3: Atomic Structure Study Guide
Section 1: History of Chemistry
1) Democritus:
a. What did he think that matter was made of?
b. What word did he coin for this?
c. Why was his atomic theory revised?
2) John Dalton:
a. On what experiments did Dalton base his ideas about atoms?
b. Describe the major concepts of his atomic theory
i. .
ii. .
iii. .
iv.
c. Describe his model of the atom.
d. Why was his theory accepted so well?
3) J. J. Thomson
a. His experiments first provided evidence of what?
b. What device did he use to make his discovery, and what evidence did he find?
c. What did people call his atomic model?
d. What do we call the particle that he discovered, and how did he know what electrical charge it had?
4) Ernest Rutherford:
a. Describe Rutherford’s gold foil experiment:
b. What evidence did the experiment produce about atoms?
c. Describe his atomic model:
5) Niels Bohr
a. How was Bohr’s atomic model similar to Rutherford’s model?
b. How do electrons move in around the atom in Bohr’s model?
c. What new concept about energy did Bohr’s model include?
d. What evidence did Bohr have to support his ideas about electrons and energy?
6) Erwin Schrödinger & Werner Heisenberg
a. How does the electron cloud model describe the location of electrons?
7) James Chadwick
a. What subatomic particle did he discover?
b. Where would you expect to find this particle?
Section 2: Atomic Structure
8) Subatomic particle descriptions:
a. Name the three subatomic particles:
b. Give the location where each can be found:
c. Give their electric charges:
d. Give their relative masses:
e. Describe the composition and characteristics of the nucleus:
9) Atomic number and mass number:
a. What determines the atomic number of an atom?
b. What determines the atomic mass of an atom?
c. How can you determine how many neutrons will be in a given atom?
d. For an atom to be neutral, what subatomic particles have to have been present in the same number?
e. What number is unique for any given element?
10) Isotopes
a. Define “isotope”:
b. What is same about all isotopes of a given element?
c. What is different between isotopes of a given element?
d. What determines the listed atomic mass for an element with many isotopes?
11) Electron energy levels:
a. The number of energy levels filled in an atom is determined by what?
b. What causes an electron to jump to a different energy level?
c. Define ground state:
d. Define excited state:
e. What causes the glow of a neon light?
f. In a flame test, which color corresponds with the highest excited energy level and which with the
lowest?
12) Complete the following table:
Element
Symbol
Atomic
Number
Se
Atomic
Mass
Mass
Number
78.96
79
Protons
Neutrons
Electrons
6
30.974
26
Xe
40
Br
79.904
80
20
25
22.990
47
13) Draw a Bohr Diagram for Carbon, Sodium, and Sulfur at their ground state and one at an excited state.