CAP Unit 02 Exam Study Booklet
This study booklet is to be completed AND corrected in entirety prior to taking the next unit exam
1) Which of the following is more metallic, what does this mean, and explain why.
Sb , Sn
Tin (Sn) is more metallic (high luster, good conductor, malleable, electron loser) compared to antimony (Sb) which is
considered to be a metalloid (semimetal). Metals tend to be found on the lower left hand side of the periodic table.
2) Arrange in order of increasing ionization energy and explain what causes these differences.
Mg , S , Si
Magnesium (Mg) has an ionization value of 738kJ/mol, silicon (Si) has an ionization value of 787kJ/mol, sulfur (S) has an
ionization value of 1000kJ/mol. While all these elements have two energy levels, the electrons within sulfur are being
pulled in by a greater nuclear charge (due to the fact that sulfur has the greatest amount of protons).
3) List the group number and family name that each one of the following belongs to.
Mn , K , Cl , Ca , Kr
Manganese (Mn) is a transition metal, potassium (K) is an alkali metal, chlorine (Cl) is a halogen, calcium (Ca) is an alkaline
earth metal, and krypton (Kr) is a noble gas.
4) Which has absorbed more energy, an atom in which an electron has moved from the second shell to the third shell, or
an otherwise identical atom in which an electron has moved from the first shell to the third shell? How does one describe
this type of atom and what occurs when the electron returns to its original shell?
It takes more energy for an atom to jump TWO levels out from the first to third shell compared to a one level jump.
When an electron is further out than it should be, the atom is said to be in the excited state. This is unstable and soon the
electron will fall back. During the fall back process, the atom releases energy…often as a photon of light.
5) Gallium in nature consists of two isotopes, gallium-69 (with a mass of 68.926u) and gallium-71 (with a mass of
70.925u). If 60.1% of all naturally occurring gallium is Ga-69, what is the calculated atomic mass?
(68.926u)(.601) + (70.925u)(.399) = 69.7u
[note: answer was limited to 3 significant figures due to math rules]
In general, it becomes more difficult to remove the most valence electron
from the element as one travels across the period from the right of the
periodic table. Recall, it is easier to remove electrons from the metals
compared to the nonmetals.
Furthermore, the anomaly can be explained by understanding the spdf
filling order. Ignoring the first energy level; lithium has an s1, beryllium is
very stable with the s2, boron starts filling the first p orbital which is fairly
easy to remove (note the decrease anomaly), carbon and nitrogen start
occupying the other p orbitals, oxygen experiences the other anomaly due
to a filling of one of the p orbitals. Then we observe a steady increase as
the p orbitals are filled with fluorine and neon.
2
2
5
ionization energy
(kj/mol)
6) Graph the ionization energy of the period 2 elements as a function of their atomic number. Explain the trend and the
anomalies within the trend.
2500
2000
1500
1000
500
0
3 4 5 6 7 8 9 10
number of protons
2
7) An excited state atom has an electron configuration of 1s 2s 2p 3s . Explain in terms of subatomic particles, how this
excited atom is electrically neutral. Furthermore, identify this element and determine the proper ground state
configuration.
2
2
5
2
+
-
The atom with a 1s 2s 2p 3s configuration is an excited sodium atom. Sodium has 11p and 11e , thus it is electrically
2 2
6 1
neutral. The ground state for sodium is 1s 2s 2p 3s .
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8) A compound has a formula of X2O3.
a) If “X” could be any metallic element within a given group, what group on the periodic table does “X” belong to?
“X” is a member of Group 3B or 3A. These elements are known to lose 3 electrons, which balances with the
three oxygen ions that take two electrons each. Note: 3B is the better answer because it is more metallic.
b) How many valence electrons does “X” have?
-
Group 3B have 2 valence electrons, but will lose three so that the next inner shell ends up with 8 valence e .
Group 3A have 3 valence electrons. Note: 3B is the better answer because it is more metallic.
c) Which element in its group could “X” be if it had the least density?
The 3B possibility would be scandium (which is the better answer), the 3A possibility would be boron.
d) Name another element besides O that would have the same subscript in a compound with “X”.
Sulfur and selenium, both with a negative 2 oxidation value, could also form similar formulas.
9) What factors determine the atomic radii of an atom? Give details on how this explains the atomic radii trend that we
observe going across the period vs. down a group.
Having more electrons and principle energy levels (electron shielding) will increase the size of the atom, whereas,
increasing the number of protons (nuclear charge) tends to pull the electrons in, thus decreases the atoms size. The
atoms tend to get smaller as one looks across the period because each of these elements have the same number of
energy levels…however, the element on the right have more protons which pulls these energy levels inward. Atoms tend
to get larger as one moves down a group because the lower elements have more energy levels.
10) List four ways to help prevent a metal from corroding. Furthermore, explain what is reduced and what is oxidized
during the corrosion that produces TiO.
Corrosion prevention can be obtained by: coating the metal, galvanizing the metal (coating with zinc), alloying the metal
(a mixture of metals), or attaching a sacrificial metal (an element with a lower electronegativity).
11) What techniques are used to obtain
a) highly reactive metals and nonmetals
b) moderately reactive metal elements
c) unreactive metals
d) noble gases
electrolysis of their compounds
chemical reduction process
can be mined in their pure state
fractional distillation of air
12) How are spectral lines produced and how can they be used to identify unknown samples?
An atom becomes excited when an electron absorbs a specific quantum of energy. This is an unstable state, and the
electron will eventually fall back to ground state. Often time, energy is released in the form of light when an electron falls
back. Every element will absorb/release specific amounts of energy, thus elements can be identified by their unique
colors of light produced when they fall back to ground state. These unique colors can be separated to produced spectral
lines which can act as a type of elemental fingerprint.
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13) Create the appropriate diagrams for nickel with regards to:
a) spdf notation
2
2
6
2
6
2
1s 2s 2p 3s 3p 4s 3d
8
b) noble gas notation
2
[Ar] 4s 3d
8
c) boxed notation















d) spdf notation of the +3 cation
2
2
6
2
6
1s 2s 2p 3s 3p 3d
7
e) what happens to the radii when the ion forms?
The atomic radii will decrease when an atom loses electrons to form a positive cation.
f) which subshells are probably responsible for color?
The unpaired “d” sublevel electrons are responsible for color and the paramagnetism of transition metals.
g) what is done (reduction/oxidation) to the ion to turn it back into an atom?
A cation must gain an electron to become reduced back into an atom.
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