Unit 2 – Atomic Theory and Periodicity Review
Section I: History
In each box, write the name of the scientist(s) associated with the statement. Choose from among the following:
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




Democritus
Dalton
Bohr
Rutherford
Thomson
Schroedinger and Heisenberg
There are small negatively charged particles inside
an atom
Thomson
His discovery was made after conducting an
experiment with gold foil
Rutherford
There is a small, dense, positively charged nucleus
Rutherford
Atoms are small, hard spheres
Dalton and Democritus
Most of an atoms mass is in the nucleus
Rutherford
Electrons are found in electron clouds, not in
defined paths
Schroedinger and Heisenberg
Electrons follow a definite path but can jump from
one path to another
Bohr
Elements combine is specific proportions to make
compounds
Dalton
Atoms are mostly empty space
Rutherford
Atoms are uncuttable
Democritus
Atoms of one element are all the same, but atoms
of different elements are different
Dalton
His theory of atomic structure led to the “plum
pudding” model of atoms
Thomson
Electron paths cannot be defined for certain
Schroedinger and Heisenberg
All substances are made of atoms
Dalton
Section II: Atomic Vocabulary (unscramble)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Weighted average of all naturally occurring isotopes of the same element. (mictoa sams) atomic mass
The building blocks of matter (moats) atoms
Positively charged particle in an atom (torpno) proton
Made up of protons and neutrons (ucselun) nucleus
Particle in an atom that has no charge (tronune) neutron
Atoms with the same number of protons but a different number of neutrons (sootpies) isotopes
Negatively charged particle in an atom (cleenrot) electron
Number of protons in a nucleus (mictoa brumen) atomic number
Regions where electrons are likely to be found (renectol scudlo) electron clouds
Sum of protons and neutrons (sams brumen) mass number
Section III: Isotopes Practice
Complete the table below.
Complete
atomic symbol
14
C
6
𝟕𝟖
I
𝟓𝟑
Atomic #
Mass #
# of protons
# of neutrons
# of electrons
6
14
6
8
6
53
78
53
25
53
𝟑𝟓
Cl
𝟏𝟕
17
35
17
18
17
54
Fe
26
𝟒
He
𝟐
26
54
26
28
26
2
4
2
2
2
238
U
92
92
238
92
146
92
11. Name the element which has the following number of particles:
a. 82 electrons, 125 neutrons, 82 protons Lead-207
b. 53 protons, 53 electrons, 74 neutrons Iodine-127
12. Naturally occurring europium consists of two isotopes with masses of 151 and 153 amu. The respective
abundances are 48.03% and 51.97%. What is the atomic mass of europium?
152 amu (or 152 g/mol)
13. Strontium consists of four isotopes. There masses and abundances are listed below. Use this data to calculate
the atomic mass of strontium.
Mass
Abundance
84
0.50%
86
9.9%
88 amu (or 88 g/mol)
87
7.0%
88
82.6%
NOTE: On the test you will need to round
average atomic masses to the correct
number of significant figures, based on the
data given.
Section IV: Unit Conversions (Mass-Moles-Atoms)
14. How many moles are in 4.14x1022 atoms of boron?
0.0687 mol
15. Determine the mass in grams of 6.8 moles of iron.
380 g
16. What is the mass of 1.62 x 1023atoms of carbon?
3.23 g
17. How many atoms are in 2.17 grams of zinc?
2.00 x 1022 atoms
Section V: Regions of the periodic table
18. Name the following regions of the periodic table.
a. Group IA alkali metals
e. Groups IB – VIIIB transition metals
b. Group IIA alkaline earth metals
f. The top row of the f block lanthanides
c. Group VIIA halogens
g. The bottom row of the f block actinides
d. Group VIIIA noble gases
19. List the six metalloids (aka semimetals). Boron, silicon, germanium, arsenic, antimony, & tellurium
20. List the seven diatomic elements. hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine
Section VI: Electron configurations and Orbital diagrams
Write the electron configurations and draw the corresponding orbital diagrams and the Lewis dot diagram for the
elements below.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
Hydrogen
Boron
Sodium
Krypton
Chromium
Phosphorus
Carbon
Oxygen
Potassium
Cobalt
Platinum
1s1
See the additional pages at the end of this
1s2 2s2 2p1
document for orbital diagrams
1s2 2s2 2p6 3s1
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
1s2 2s2 2p6 3s2 3p6 4s2 3d4
1s2 2s2 2p6 3s2 3p3
1s2 2s2 2p2
1s2 2s2 2p4
1s2 2s2 2p6 3s2 3p6 4s1
1s2 2s2 2p6 3s2 3p6 4s2 3d7
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d8
Write the abbreviated electron configurations and orbital diagrams for the elements below.
32.
33.
34.
35.
36.
Platinum
Plutonium
Neodymium
Lead
Cesium
[Xe] 6s2 4f14 5d8
[Rn]7s2 5f6
[Xe]6s2 4f4
[Xe] 6s2 4f14 5d10 6p2
[Xe]6s1
Describe each of the following rules for electrons filling orbitals in an electron cloud.
37. Aufbau rule – each electron occupies the lowest energy orbital available
38. Pauli exclusion principle – a max of two electrons may occupy one orbital but the must have opposite spins
39. Hund’s rule – single electrons must occupy each equal-energy orbital before an opposite spin electron is
added
40. Heisenberg uncertainty principle – it is impossible to know both the velocity and position of an electron at the
same time
Section VIII: Periodic Trends
41. Rank the following elements by increasing atomic radius: carbon, aluminum, oxygen, potassium.
O, C, Al, K
42. Rank the following elements by increasing electronegativity: sulfur, oxygen, neon, aluminum.
Ne, Al, S, O
43. Rank the following elements by increasing first ionization energy: bromine, strontium, arsenic, calcium
Sr, Ca, As, Br
44. Why does fluorine have a higher first ionization energy than iodine? Fluorine’s valence shell is closer to the
nucleus that iodine’s (fluorine has fewer shielding electrons). Thus, the nucleus has a stronger attraction for
fluorine’s valence electrons, making them harder to remove.