Name: ____________________________________________
AP Chemistry
Unit 2 Take Home Test: Atomic Structure & Periodicity
Directions (1 – 23): Circle the choice that best answers each question.
1. Which supports the conclusion that the energy of electrons in atoms is quantized?
(A) Mass spectrometer beam distribution
(B) Emission spectra of gaseous elements
(C) Cathode ray deflection by a magnetic field
(D) Scattering of alpha particles by metal foil
(E) Radioactive transmutation of elements
2. All the following statements concerning the alkali metals are true EXCEPT:
(A) Francium is the least electronegative.
(B) They form ions with a 1+ charge
(C) Lithium has the smallest atomic radius.
(D) First ionization energy increases with atomic number
(E) They are not found in pure form in nature.
3. All of the following exist as a diatomic gaseous elements at room temperature EXCEPT:
(A) Nitrogen
(D) Chlorine
(E) Oxygen
(B) Radon
(C) Fluorine
4. Which of the following is true about the halogen family?
(A) Its valence electrons are of the form ns2np4
(B) Atomic radius decreases with increasing atomic number
(C) It combines with group IIA metals in binary compounds of the form XY
(D) It contains members that naturally exist in each of the 3 states of matter
(E) All its members are monatomic
5. When a solution of strontium chloride is ignited, the color of the flame is
(A) blue
(D) red
(B) orange
(E) green
(C) purple
Base your answer to the following questions on the choices below.
(A) Pauli exclusion principle
(B) Heisenberg uncertainty principle
(C) Hund’s rule
(D) Wave nature of matter
(E) Photoelectric effect
6. Which gives support to the particle theory of light? ____ E
7. Which concept was first postulated by de Broglie? ____ D
8. Which states that electrons half-fill an orbital with parallel spin before completely filling it? ____ C
9. Which states that you cannot have simultaneous knowledge of an electron’s position and momentum?
____ B
10. Which predicts that an oxygen atom in the ground state is paramagnetic? ____ C
11. Which states that in an atom, no two electrons can have the same set of quantum numbers? ____ A
Base your answer to the following question on the elements below.
(A) Cl
(B) At
(C) Li
(D) Ne
(E) Ca
12. Which element has a violent reaction when combined with cold water? ____C
Base your answers to the following questions on the electron configurations below:
(A) 2s1
(B) [Ar] 3d104s24p1
(C) [Kr] 4d105s25p3
(D) [Ne] 3s2
(E) [Kr]4d105s25p6
13. An alkaline earth metal D
14. An alkali metal A
15. An element with Z=31 B
16. A metalloid C
17. A noble gas E
Base your answers to the following questions on the elements listed below.
(A) Sulfur
(B) Bromine
(C) Silicon
(D) Zinc
(E) Fluorine
18. A semi-conductor C
19. A d-block element D
20. A liquid at room temperature B
21. A yellow solid A
22. The most electronegative element E
23. Which quantum numbers represent the highest energy electron of bromine’s valence orbital?
(A) 4, 0, 1, ½
(B) 4, 2, 0, ½
(C) 4, 1, 2, ½
(D) 4, 0, 0, ½
(E) 4, 1, 1, ½
Directions (24-28): Answer the following questions on a separate sheet of paper. Explanations should be clear
and well organized. Examples and equations should be included in your responses where appropriate. Show all
work for any calculations. Attention should be paid to units and significant figures in calculations.
24. A major line in the emission spectrum of neon corresponds to a frequency of 4.341014 s-1. Calculate the
wavelength, in nanometers, of light that corresponds to this line.
c = 
 3.0  10 8 m s-1 10 9 nm

= 
= 690 nm
c 4.34  1014 s-1
1m
25. In the upper atmosphere, ozone molecules decompose as they absorb ultraviolet (UV) radiation, as shown
by the equation below. Ozone serves to block harmful ultraviolet radiation that comes from the Sun.
O3(g) UV
 O2(g) + O(g)
A molecule of O3(g) absorbs a photon with a frequency of 1.001015 s-1.
(i) How much energy, in joules, does the O3(g) molecule absorb per photon?
E = h = (6.6310-34 J s)(1.001015 s-1) = 6.6310-19 J
(ii) The minimum energy needed to break an oxygen-oxygen bond in ozone is 387 kJ mol-1. Does a
photon with a frequency of 1.001015 s-1 have enough energy to break this bond? Support your answer
with a calculation.
6.02  10 23 1 kJ
 3 = 399 kJ
1 mol
10 J
This is more than 387 kJ, so there is enough energy to break the bond.
6.6310-19 J 
26. Suppose that a stable element with atomic number 119, symbol Q, has been discovered.
(a) Write the ground-state electron configuration for Q, showing only the valence electron(s).
8 s1
(b) Would Q be a metal or a nonmetal? Explain in terms of electron configuration.
Q is a metal. It has one valence electron that it easily loses, consistent with the other alkali metals in its
family.
(c) On the basis of periodic trends, would Q have the largest atomic radius in its group or would it have the
smallest? Explain in terms of electronic structure.
Q would have the largest atomic radius in its group. Every time another subshell is added to an element, it
becomes larger.
(d) What would be the most likely charge of the Q ion in stable ionic compounds?
+1
27. The electron affinities of five elements are given below.
12 kcal/mole
13Al
Si
32 kcal/mole
14
17 kcal/mole
15P
48 kcal/mole
16S
87 kcal/mole
17Cl
Define the term “electron affinity”. For the elements listed above, explain the observed trend with the increase
in atomic number. Account for the discontinuity that occurs at phosphorus.
Electron affinity is defined as the energy released when a gaseous atom gains an electron to form a negative ion.
Across a period, Z increases while the number of principal energy levels containing electrons remains the
same. Because of this, the effective nuclear charge increases and atomic radius decreases across a period.
Therefore, the added electron in going from Al to Si and from P to S to Cl is pulled in closer to the nucleus and
more energy is released (the electron affinity is greater).
A break in this trend occurs at P because the 3p subshell is exactly half-filled, resulting in a configuration
with the least amount of electron-electron repulsion. The extra electron must be paired with an existing electron,
thus increasing electron-electron repulsion and reducing the amount of energy released when it is added to form
P–.
28. Discuss some differences in physical and chemical properties of metals and nonmetals. What characteristic
of the electronic configuration of atoms distinguishes metals from nonmetals? On the basis of this characteristic
explain why there are many more metals than nonmetals.
metals
non-metals
Physical properties:
melting
rel. high
rel. low
points
elec. conduct. good
luster
high
physical state most solids
[etc.]
Chemical properties:
redox agents reducing
electropositive
oxides
basic
react with
nonmetals
[etc.]
insulators
little or none
gases, liq. or solids
oxidizing
electronegative
acidic
metals & non-metals
Electron configurations: Metals have valence electrons in s, d, and/or f subshells of their atoms. (A few metals
have atoms with one or two electrons in p subshells.) Nonmetals have valence electrons in the s and p subshells
of their atoms.
There are more metals than nonmetals because filling d and f orbitals in a given energy level involves the atoms
of 10 and 14 elements, respectively. In the same energy levels, the maximum number of elements that can be
filling p orbitals is six.