CHM 111
Chapter 8 Worksheet: Periodic properties of elements
Answers (For simpler problems, only every 2nd or 3rd answer is given)
Name:
_______________________________
Q1. Draw the orbital diagram for the following (with arrows like ↑↓):
A) Cl
1s: ↑↓
2s: ↑↓
3s: ↑↓
2p: ↑↓ ↑↓ ↑↓
3p: ↑↓ ↑↓ ↑
B) O
Q2. Write the condensed electronic configurations for the following (Example: Na is [Ne]3s1):
(A) Ni _____ [Ar]3d84s2_____________
(B) Pd (should be diamagnetic) ___________________________
(C) Cs ___________________________
(D) Gd ______ [Xe]4f75d16s2__________
(E) Br _____________________________
(F) P ___________________________________
(G) Cr (all valence electrons unpaired) __________ [Ar]3d54s1____________________
(H) Hg ______________________________________
Q3.
A particular element has the following ionization energies (kJ/mole):
IE1 =1086, IE2 = 2352, IE3 = 4619, IE4 = 6221, IE5 = 37820, IE6= 47620
Which main group of the periodic table does the element belong to? Explain the reasoning for your answer.
Group 4 (14), with C, Si, Ge, etc. because the first two electrons are relatively easy to remove, the next
two are a bit harder (the IE suddenly jumps up after the 2nd electron), and especially after the 4th electron, removing the
5th and more is MUCH harder. This corresponds to a configuration of something like 1s22s22p2 or …2p63s23p2 where
there are 4 valence electrons, which are relatively easy to remove (the p2 a bit easier than the s2), but after that, we
have to dig into the core electrons, which are far more difficult to remove.
Q4. In each of the following pairs, circle the element with the larger first ionization energy:
a) B or N
b) Se or S
c) Cl or Ge
d) Li or Rb
e) Al or F
Q5.
In each of the following pairs, circle the element with the larger radius.
a) Co or Co2+
b) Al or Ar
c) As or Bi
d) Tl or In
e) S or S2-
f) Al3+ or Al
A neutral element was found to have an electron configuration of: 1s2 2s2 2p4 3d1.
Assuming it is a neutral atom, identify the element and state whether the element is in the ground state or an
excited state.
Q6.
Element: ____F______
Q7.
Ground or excited?
Arrange the elements Sr, In and Te in the correct order for each trend below, and clearly explain the reason for
the order you chose in each case.
a) Increasing atomic radius (from small to big)
Te, In, Sr because further left on periodic table means bigger radius
b) Increasing first Ionization energy (from low to high)
c) Increasing electron affinity (from low to high)
Q8. For each of the following series, list the species in the appropriate order.
a) Na, K, K+
(Increasing radius, from small to big)
+
K , Na, K
b) S, Cl, Cl-
(decreasing radius, from big to small)
c) Mg, Ca, Ba
(most negative to least negative electron affinity)
d) Mg, Si, Cl
(increasing First ionization energy, from low to high)
Mg, Si, Cl
e) Be, F, O,
(least negative to most negative electron affinity)
Q9. First, write the condensed electron configurations for the following elements. Then, predict the most likely ion
that each element will form, and write the condensed electron configuration for that ion.
Element
Electron configuration of element
ion
Electron configuration of ion
Cl
[Ne]3s23p5
Cl-
[Ne] 3s23p6
[Ar]3d54s2
Mn2+
[Ar]3d5
[Kr]3d104s1
Ag+
[Kr]3d10
K
Mn
S
Pb
Ag
I
Q10.
Consider the following electronic configurations.
a)
b)
c)
d)
1s2, 2s2, 2p5
1s2, 2s2, 2p6
1s2, 2s2, 2p6, 3s1
1s2, 2s2, 2p6, 3s2
Pick the electron configuration that best fits each of the qualities below:
Lowest First Ionization energy (c)
Highest first ionization energy
Most negative electron affinity (a)
Lowest second ionization energy
Highest second ionization energy (c)
Q11.
In each of the following pairs, circle the element with the larger radius.
a) S or As
d) Ga or As
b) Si or N
e) C or F
c) I or Br
f)
Cl or Br