Name: ___________________________ Date: _________________ Period:__________
Atomic Structure and Matter Chemistry Review
Exam on Tuesday, September 22
Concepts/Definitions
1. Identify and explain/describe the experiments and discoveries attributed to (make sure you can
explain the cathode ray and gold foil experiment)
Dalton: Dalton did not perform an experiment, but he did come up with 5 postulates. There are
slightly different versions of them. We discussed the following in class:
 All matter is made of tiny particles called atoms
 Atoms are rearranged during chemical reactions
 All atoms of the same element are identical (false)
 Atoms cannot be created or destroyed, or divided into smaller parts (false – they can be
divided into smaller parts, and they can be split)
 Atoms of different elements combine to form compounds
Thomson: He discovered electrons while experimenting with cathode ray tubes. He came up with
the plum pudding model of the atom, where the whole atom is positive and the negative electrons
are spread throughout the atom (like raisins in plum pudding).
Bohr: He came up with the idea of electrons being on energy levels, which are drawn as rings
around the nucleus in his model.
Rutherford: He discovered that atoms have a dense central nucleus while performing the gold foil
experiment. He shot alpha particles at a piece of gold foil. According to the plum pudding model,
all of the alpha particles should have easily shot straight through the gold atoms, but some were
deflected and others even bounced back. This was because these particles hit the nucleus of the
gold atoms.
Pre-AP: Millikan: He performed the oil drop experiment and discovered the mass-to-charge ratio
of an electron.
2. Put a check next to Dalton’s Postulates that are true and an X next to Dalton’s Postulates that
have been proven wrong:
False All matter consists of indivisible particles called atoms. All matter is made of atoms, but
atoms are not indivisible.
True. Atoms of the same element are similar in shape and mass, but differ from the atoms of
other elements. They are similar, but are not all identical. Isotopes are atoms of the same
element that have different masses, because they have different numbers of protons.
True Atoms cannot be created or destroyed. However, we can combine some smaller atoms into
larger atoms, and we can divide atoms (that’s how nuclear weapons and energy work).
True Atoms of different elements may combine with other elements in whole number ratios to
form compounds. I didn’t discuss the “whole-number ratio” idea in class. Just focus on the main
idea of atoms combining with those of other elements to form compounds.
Name: ___________________________ Date: _________________ Period:__________
Atomic Structure and Matter Chemistry Review
Exam on Tuesday, September 22
True Atoms of same element can combine in more than one ratio to form two or more
compounds. Again, this not discussed in class because it’s unnecessary information for this test.
True The atom is the smallest unit of matter that can take part in a chemical reactions. Atoms
can be divided into smaller parts, but the word “unit” implies all of the particles together as a
whole.
Match the keyword with the proper definition:
3. Isotope
A
a) Atoms of the same element with different numbers of neutrons
4. atomic number F
5. mass number
6. proton
B
7. neutron
D
E
b) This subatomic particle has a positive charge.
c) This subatomic particle has a negative charge.
d) This subatomic particle has no charge (neutral).
e) This number indicates the total number of protons and neutrons in
an atom.
f) This number indicates the number of protons in an atom and
defines an element.
8. electron C
Questions:
9. Determine the number of subatomic particles for
42Ca.
Protons: 20 (know this from the atomic number, which is on the periodic table)
Neutrons: 22 (42-20, mass number – atomic number)
Electrons: 20 (same as protons)
10. Determine the number of protons, neutrons, and electrons of 129Te.
b. 129 protons, 129 neutrons, 129
a. 52 protons, 129 neutrons, 52 electrons
electrons
d. 52 protons, 52 neutrons, 52 electrons
c. 52 protons, 77 neutrons, 52 electrons
11. Find how many neutrons an atom has based on the data given
 How many neutrons does the element Silver-110 have?
a. 110
b. 108
d. 63
c. 173

If an atom has an atomic mass of 207 and has 82 protons, how many neutrons does it have?
a. 289
b. 207
Name: ___________________________ Date: _________________ Period:__________
Atomic Structure and Matter Chemistry Review
Exam on Tuesday, September 22
c. 125
d. 82
12. Perform average atomic mass calculations given isotope data.
Chlorine has 2 naturally occurring isotopes: Cl-35 (34.9689 amu) makes up 75.40%, and Cl-37
(36.9659 amu) accounts for 24.60%. What is the average atomic mass of chlorine. (use two
decimal places in your answer)
b. 3546.02 amu
a. 35.46 amu
c. 35.97 amu
d. 36 amu
13. Draw and label the Bohr model of Chlorine. Label each particle with the correct name. Be sure to
evenly distribute electrons in the proper locations. If a particle has a charge, label it.
It should have 17 protons in the nucleus, and 17 electrons on the rings: 2 on the first ring, 8 on
the second ring and 7 on the third ring. (since the question does not give us a mass number, we
cannot calculate the neutrons).
14. Graphene is 207 times stronger than steel by weight, conducts heat and electricity extremely
well, and is transparent. It is made entirely out of just carbon atoms. Which classification of
matter does graphene fall under?
a. element
c. heterogeneous mixture
b. compound
d. homogeneous mixture
15. Glucose (C6H12O6) is a sugar created from the process of photosynthesis. First, state what
classification of matter it is (element, compound, heterogeneous mixture, homogeneous mixture)
and then state whether or not this process is a physical or chemical change.
Compound (it has a chemical formula, so it has to be a compound).
Chemical change. If a compound is created, then it must be a chemical change.
Name: ___________________________ Date: _________________ Period:__________
Atomic Structure and Matter Chemistry Review
Exam on Tuesday, September 22
16. LEVEL ONLY: When baking soda and vinegar are mixed together, a gas is formed from the
reaction that takes place. Is this a physical or chemical change? Explain why.
Chemical change. A gas forming when chemicals are mixed is a sign of a chemical change. (gases
can form during physical changes – such as evaporation – but if chemicals are being mixed (and
none of those chemicals were gases to begin with) you can be certain it is a chemical change).