Exam 3
Chem 1A
Dr. Somma
Name_______________________
October, 20 2008
Watch units and significant figures!!
Return the card after completing the exam.
1. (22 pts.)
(i)
Multiple choice.
100 points
10 bonus points
Show all work to receive full credit!!
Circle the correct answer.
Transition metal elements have atoms or ions with partially filled:
a.
b.
c.
d.
s subshells.
d subshells.
p subshells.
f subshells.
(ii)
The maximum number of electrons that can occupy an energy level described by the principal
quantum number, n, is
a.
n.
b.
n2.
c.
2n.
d.
2n2.
(iii)
How many valence electrons does the carbon atom have?
a.
b.
c.
d.
(iv)
Which of the following elements has the highest first ionization energy?
a.
b.
c.
d.
(v)
Na
Al.
Tl
Cl.
The electron configuration of a copper atom is:
a.
b.
c.
d.
(vi)
4.
2.
6.
1.
[Ar]4s24d4.
[Ar]4s13d10.
[Ar]4s23d9.
none of the above.
Orbital energies for the electron in the H atom depend on which quantum numbers?
a.
b.
c.
d.
n and l.
n.
n, l, ml and ms.
n, l, and ml.
(vii)
Identify the transition metal ion that is isolelectronic to Fe3+:
Mn4+.
Al3+.
Mn2+.
Co2+.
a.
b.
c.
d.
(viii) Which of the following set of quantum numbers is (n, l, ml and ms) invalid:
a.
b.
c.
d.
(ix)
(4, 3, -2, + 1/2).
(3, 0, -1, - 1/2).
(4, 2, -2, + 1/2).
(2, 1, 1, - 1/2).
Which scientist proposed the wave-particle duality of matter in 1924?
a.
b.
c.
d.
(x)
The total number of electrons that can be assigned to the n = 4 shell is?
a.
b.
c.
d.
(xi)
Einstein.
Bohr.
De Broglie.
Heisenberg.
8.
64.
32.
50.
Which of the following element has the greatest metallic character?
a.
b.
c.
d.
Br.
Se.
Ni.
As.
2. (12 pts.)
The first ionization energies of Li, Be, and C are 5.4, 9.3 and 11.3 eV. Keeping in
account their electron configuration of these elements, explain what you predict for the ionization
energy of B.
3. (12 pts.) a). What is the big difference between the energy level diagram for hydrogen and that for
any multi-electronic atom? Hint: Think about the quantum mechanical meaning of
“degenerate”.
b). What does the Pauli Exclusion Principle say?
4. (14 pts.)
a). How much energy is required for an electron in a hydrogen atom to make the
transition from the n=2 energy level to the n=3 energy level.
b). What is the wavelength of a photon having this energy.
c). Give the region of the electromagnetic spectrum in which the photon will be found.
5. (12 pts.)
Given that the position of a hydrogen atom is known to within 1.00 pm (picometer),
utilize the Heisenberg principle to compute the uncertainty in the velocity of the atom.
6. (14 pts.)
a) Write the electron configuration for the ground state of the atom of cobalt (Co).
(please do not use noble gas core abbreviations for your answer).
b) Draw the orbital energy level diagram for a ground state of Co (please, be sure to
label the orbitals)
c). Cobalt commonly exist as Co3+ ion. How does the diagram drawn for part b) have to
be changed to represent Co3+? Sketch the change to the right of the diagram drawn for
part b); (please, be sure to label the orbitals).
7. (14 pts.)
The element Bismuth (Bi, atomic number 83) is the heaviest member of group 5A. A
salt of this element, bismuth subsalicylate, is used as active ingredient of Pepto-Bismol®.
a) The atomic radii of thallium (Tl) and Lead (Pb) are 1.48 Å and 1.47 Å respectively. Using these
values and your knowledge about the trends of atomic radii in the periodic table, predict the atomic
radius of Bi. Explain your answer.
b) What accounts for the general increase in the atomic radius going down the group 5A elements?
c) This element is also used as an ingredient in low- melting metal alloys. The element itself is a brittle
white crystalline solid. How do these characteristics fit with the fact that Bi is in the same group with
nonmetallic elements such as nitrogen and phosphorous?
d) (Bonus Question) Bi2O3 is a basic oxide. Write the balanced chemical equation for its reaction with
dilute nitric acid.
If 6.77 g of Bi2O3 is dissolved in dilute acidic solution to make up 500 mL of solution, what is the
molarity of the solution Bi3+?