Assignment 06 A
1- What is the energy in joules of an electron undergoing a transition from n = 3 to n = 5 in a Bohr hydrogen
atom?
a) -3.48 x 10-17 J
b) 2.18 x 10-19 J
c) 1.55 x 10-19 J
d) -2.56 x 10-19 J
(You correctly substituted ni and nf into the equation E = (2.18 x 10-18)(ni-2 - nf-2)).
2- How many photons of frequency 1.50 x 1014 s-1 are needed to give 30.1 J of energy?
a) 3.03 x 1020 photons
b) 9.94 x 1020 photons
c) 9.94 x 10-20 photons
d) 0.450 photons
e) 1.01x 1019 photons
(Determine the energy of a single photon by taking the product of Planck's constant and the given
frequency. Divide this into the total energy to see how many photons would be required.)
3- Of the following regions of the electromagnetic spectrum, which one has the shortest wavelength?
a) gamma rays
b) radio waves
c) infrared
d) microwaves
e) X rays
f) Ultraviolet
(Gamma rays are very high in energy per photon.
4- In the Bohr theory, which of the following emissions will have the largest energy?
a) n = 2 going to n = 3
b) n = 4 going to n = 2
c) n = 4 going to n = 3
d) n = 3 going to n = 2
e) n = 5 going to n = 4
(The energy separation between principal energy levels is greater for lower values of nf and
larger n differences.)
5- The Heisenberg uncertainty principle states that it is impossible to precisely know both the position and the
___________ of an electron in an atom.
a) shape
b) mass
c) color
d) momentum
(The Heisenberg uncertainty principle deals with position and momentum as related variables.)
6- Write the electron configuration for the atom Zn, abbreviating with the appropriate noble-gas inner core.
a) [Ar]4s24d10
b) [Kr]4s24d10
c) [Ar]4s13d10
d) [Kr]4s23d10
e) [Ar]4s23d10
(Zn has a 3d10 configuration; Argon is the inert gas prior to it.)
7- In the hydrogen atom, which of the following orbitals has the lowest energy?
a) 5s
b) 4p
c) 6d
d) 6f
e) 3p
(Energy increases with n for this one electron system.)
8- How many orbitals are there in the 4p subshell?
a) 2
b) 5
c) 3
d) 1
e) 4
(All p subshells (regardless of the principal quantum number) have three orbitals.)
9- Which of the following particles traveling at 1.00 x 104 m/s has the largest de Broglie wavelength?
a) electron
b) neutron
c) helium nucleus
d) proton
(The electron has the smallest mass of these four choices and thus the largest de Broglie
wavelength.)
10- What is the wavelength of radiation that has a frequency of 5.11 x 1011 s-1?
a) 5.87 x 10-12 m
b) 5.87 x 10-2 m
c) 5.87 x 10-4 cm
d) 5.87 x 10-4 m
(The speed of light divided by the frequency gives the wavelength.)
11- The de Broglie wavelength of an electron is 8.7 x 10-11 m. The mass of this electron is 9.1 x 10-31 kg. What is
the velocity in m/s of this electron (h = 6.63 x 10-34 J·s)?
a) 1.2 x 10-7 m/s
b) 8.4 x 106 m/s
c) 6.9 x 10-54 m/s
d) 7.3 x 10-4 m/s
(Substitute the wavelength and mass of an electron into the de Broglie relation and solve for the
velocity. Remember that 1 J = 1 kg·m2/s2.)
12- Which one of the following elements has one or more unpaired electrons in the ground state?
a) calcium
b) mercury
c) neon
d) cadmium
e) zirconium
(Zirconium has two unpaired electrons in the valence shell (5s24d2 configuration).)
13- What is the maximum number of electrons that can occupy the subshell 3d?
a) 1
b) 3
c) 5
d) 2
e) 6
f) 10
(There are five orbitals in a d subshell, so a total of 10 electrons can be in a d subshell, 2 electrons
occupying each orientation of each type of orbital.)
14- How many electrons populate the (complete) second electron shell in the ground state of atomic argon?
a) 6
b) 18
c) 2
d) 36
e) 8
(The second electron shell, when complete, contains eight electrons (2s22p6).)
15- What is the relationship between the number of nodes in an s orbital and the principal quantum number?
a) The number of nodes equals the square of the principal quantum number.
b) The number of nodes equals the principal quantum number.
c) The number of nodes equals the principal quantum number minus 1.
d) The number of nodes equals the principal quantum number plus 1.
(The first shell s-type orbital has no nodes present.)
16- For the 25Mn atom, which subshell is partially filled?
a) 3d
b) 4s
c) 3s
d) 4p
e) 4d
(This subshell has five electrons in it, but it can hold up to10 electrons.)
17- Identify the specific element that corresponds to the following electron configuration: [Ne]3s23p1
a) B
b) Al
c) Ga
d) C
e) Si
(Al is in the third period and is a member of the group having a ns2np1 valence shell configuration.)
18- Which of the following is not true?
a) The inner transition elements have valence electrons in an f subshell.
b) It is possible to have up to 10 electrons in a p subshell.
c) There are only two possible values for the spin quantum number.
d) The lowest value for the principal quantum number, n is 1.
(There are just three orientations of the p-orbital, each of which can only accept 2 electrons,
provided each has a different spin quantum number.)
19- How many different ml values are possible for l = 3, an f orbital?
a) 7
b) 5
c) 1
d) 2
e) 3
(The possible values for ml are +3, +2, +1, 0, −1, −2, and −3.)
20- Write the electron configuration for the atom Rb, abbreviating with the appropriate noble-gas inner core.
a) [Ne]4s1
b) [Ar]4s1
c)
d)
e)
f)
[Ne]5s1
[Ar]5s1
[Kr]4s1
[Kr]5s1
(Kr is the inert gas prior to Rb; Rb is in the fifth period, group 1.)
21- Which one of the following represents an incorrect set of quantum numbers for an electron in an atom
(arranged as n, l, ml, and ms)?
a) 3, 3, 3, 1/2
b) 2, 1, −1, −1/2
c) 1, 0, 0, 1/2
d) 5, 4, −3, ½
(This set is incorrect because the second number (l) must be less than the first (n).)
22- For n = 4, what are the possible values of l?
a) 0, 1, 2, 3, 4, 5
b) 0, 1, 2, 3, 4
c) 1, 2, 3, 4
d) 0, 1, 2, 3
e) 1, 2, 3
(Remember that l can equal any integer from 0 to n − 1.)
23- Which of the following sets is not an acceptable set of quantum numbers?
a) n = 2, l = 1, ml = +1
b) n = 3, l = 1, ml = −3
c) n = 1, l = 0, ml = 0
d) n = 7, l = 3, ml = +3
(m = −3 is less than −l, which is not allowed.)
24- For the 25Mn atom, which subshell is partially filled?
a) 3s
b) 4s
c) 3d
d) 4p
e) 4d
(This subshell has five electrons in it, but it can hold up to 10 electrons.)
25- Give the values for n, l, and ml for each orbital in the 2p subshell.
a) n = 2, l = 2, ml = 2, 1, 0, −1, −2
b) n = 2, l = 1, ml = 1, 0, −1
c) n = 2, l = 1, ml = 0
d) n = 2, l = 0, ml = 0
(The 2p subshell has a principal quantum number of 2 and l = 1. There are three possible orbitals.)
26- How many electrons can occupy the 5f subshell?
a) 8
b) 6
c) 14
d) 10
e) 12
(The number of orbitals is given by the following values for ml = +3, +2, +1, 0, −1, −2, −3. The
total possible number of electrons is twice the number of orbitals since there can be up to two
electrons occupying each orbital if they each have opposite spins.)
27- Identify the specific element that corresponds to the following electron configuration: [Kr]5s24d105p4
a) I
b) In
c) Sb
d) Sn
e) Te
(The 5p4 configuration indicates that this is in period 5, column 4 in the p-block.)