Download Unit 1 Problem Set

Nomen: ____________________________________________________
Unit 1: Atomic Structure Problem Set
NOTE: Problem sets are always due the day before the unit exam. 5 points of extra credit is
available for the first person to submit a completed problem set if that problem set is mostly
accurate and can be used as an answer key with minimal changes.
1. Give the number of protons, neutrons and electrons in the following atoms:
7533As
Uranium-238
Bromine-81
Protons
Neutrons
Electrons
(Total 3 marks)
2. Give the number of protons, neutrons and electrons in the following atoms:
12753I-1
14058Ce+3
Calcium-40,
Charge = +2
Protons
Neutrons
Electrons
(Total 3 marks)
3. Which of the following species contain more electrons than neutrons? Show work!
A 21H
B 115B
C 168O2−
D 199F−
(Total 1 mark)
4. Which of the following gives the correct composition of the 71Ga+ ion present in the
mass spectrometer when gallium is analyzed.
(Total 1 mark)
5. Use the Periodic Table to find the percentage abundance of neon-20, assuming that
neon has only one other isotope, neon-22.
(Total 2 marks)
6. Magnesium has three stable isotopes – 24Mg, 25Mg, and 26Mg. The lightest isotope
has an abundance of 78.90%. Calculate the percentage abundance of the other
isotopes. Show all work.
(Total 2 marks)
7. Chromium has four naturally occurring isotopes, and their names, masses and
relative abundance are given below.
Isotope
Natural Abundance (%)
50Cr
4.35
52Cr
83.79
53Cr
9.50
54Cr
2.36
Calculate the relative atomic mass of chromium to the correct number of significant
digits. Show all work.
(Total 2 marks)
8. Rubium has a relative atomic mass of 85.47 and consists of two naturally occurring
isotopes, 85Rb (u=84.91) and 87Rb (u= 86.91). Calculate the percentage composition
of these isotopes in a naturally occurring sample of rubidium. Show all work.
(Total 2 marks)
9. (a) Explain why the relative atomic mass of argon is greater than the relative atomic
mass of potassium, even though the atomic number of potassium is greater than the
atomic number of argon.
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(b) Deduce the numbers of protons and electrons in the K+ ion.
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(c) Deduce the electron arrangement for the K+ ion.
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(Total 3 marks)
10. Identify a radioactive isotope of carbon and state one of its uses.
(Total 1 mark)
11. (a) List the following types of electromagnetic radiation in order of increasing
wavelength (shortest first).
I.
II.
III.
IV.
Yellow light
Red light
Infrared radiation
Ultraviolet radiation
(b) Distinguish between a continuous spectrum and a line spectrum.
(c) The thinning of the ozone layer increases the amount of UV-B radiation that
reaches the Earth’s surface.
Type of Radiation
Wavelength / nm
UV-A
320–380
UV-B
290–320
Based on the information in the table above explain why UV-B rays are more
dangerous than UV-A.
(Total 5 marks)
12. In the emission spectrum of hydrogen, which electronic transition would produce a
line in the visible region of the electromagnetic spectrum? Show all work.
A.
n = 2 →n = 1
B.
n=3→n=2
C.
n=2→n=3
D.
n=∞→n=1
(Total 1 mark)
13. Which describes the visible emission spectrum of hydrogen? Show all work
A.
A series of lines converging at longer wavelength
B.
A series of regularly spaced lines
C.
A series of lines converging at lower energy
D.
A series of lines converging at higher frequency
(Total 1 mark)
14. Identify which of the following provide evidence to support the Bohr model of the
hydrogen atom?
I The energy of the lines in the emission spectra of atomic hydrogen.
II The energy of the missing lines in the absorption spectra of helium as seen
from the sun.
III The relative intensity of the different spectral lines in the emission
spectrum of atomic hydrogen.
A.
I only
C.
C I and II
B.
B II only
D.
D I and III
(Total 1 mark)
15. What is the electron configuration of vanadium?
A.
1s22s22p63s23p63d24s3
B.
1s22s22p63s23p63d34s2
C.
1s22s22p63s23p63d44s1
D.
1s22s22p63s23p63d5
(Total 1 mark)
16. State two ways in which the Schrö dinger model of the hydrogen atom differs from
that of the Bohr model.
(Total 2 marks)
17. What is the order of increasing energy of the orbitals within a single energy level?
A.
B.
C.
D.
d<s<f<p
s<p<d<f
p<s<f<d
f<d<p<s
(Total 1 mark)
18. An ion has the electron configuration 1s2 2s2 2p6 3s2 3p6 3d10. Which ion could it be?
A.
B.
C.
D.
Ni2+
Cu+
Cu2+
Co3+
(Total 1 mark)
19. State the full ground-state electron configuration of the following ions.
(a) O2–
(b) Cl–
(c) Ti3+
(d) Cu2+
(Total 4 marks)
20.
a. State the full electron configuration of Neon.
b. State the formulas of two oppositely charges ions that have the same electron
configurations as Neon
(Total 3 marks)
21. Explain, using electron orbital diagrams to show their electron configurations, why
gold and silver are particularly stable. Explain any exceptions to the Aufbau
Principal.
(Total 4 marks)
22. Explain, using electron orbital diagrams, why the two most common ions for Iron
(Fe) are +2 and +3.
(Total 4 marks)
23. Values for the successive ionization energies for an unknown element are given in
the table below.
First ionization
Second
Third ionization
Fourth ionization
energy / kJ mol–1 ionization energy energy / kJ mol– energy / kJ mol–
/ kJ mol–1
1
1
420
3600
4400
5900
In which group of the periodic table would the unknown element be found?
A.
1
B.
2
C.
3
D.
4
(Total 1 mark)
24. The first ionization energies of the Period 3 elements Na to Ar are given in Section 8
of the IB data booklet .
a. Explain the general increase in ionization energy across the period.
b. Explain why the first ionization energy of magnesium is greater than that of
aluminium.
c. Explain why the first ionization energy of sulfur is less than that of
phosphorus.
(Total 3 marks)
25. Identify the sub-level which does not exist.
A.
5d
B.
4d
C.
3f
D.
2p
(Total 1 mark)
26. Which is the correct order of orbital filling according to the Aufbau Principle?
A. 4s 4p 4d 4f
B. 4p 4d 5s 4f
C. 4s 3d 4p 5s
D. 4d 4f 5s 5p
(Total 1 mark)
27. State the full ground-state electron configuration of the following elements.
A.
V
B.
K
C.
Se
D.
Sr
(Total 1 mark)
28. Determine the total number of electrons in d orbitals in a single iodine atom.
A.
5
B.
10
C.
15
D.
20
(Total 1 mark)
29. Explain why a potassium atom contains an electron in a 4s orbital with no electrons
in a 3d orbital whereas a copper(I) ion, Cu+ has the electronic configuration
[Ar]3d10 with no electrons in the 4s orbital.
(Total 2 marks)
30. Identify the excited state (i.e. not a ground state) in the following electron
configurations.
A.
[Ne] 3s23p3
B.
[Ne] 3s23p34s1
C.
[Ne] 3s23p64s1
D.
[Ne] 3s23p63d14s2
(Total 1 mark)
31. Deduce the number of unpaired electrons present in the ground state of a titanium
atom.
(Total 1 mark)
32. State the ground-state electron configuration of the
Fe3+
ion.
(Total 1 mark)
33. State the electron configuration of the following transition metal ions by filling in
the boxes below. Use arrows to represent the electron spin.
(Total 4 marks)
34. Only a few atoms of element 109, meitnerium, have ever been made. Isolation of an
observable quantity of the element has never been achieved, and may well never be.
This is because meitnerium decays very rapidly.
(a) Suggest the electron configuration of the ground-state atom of the element.
(b) There is no g block in the Periodic Table as no elements with outer electrons in g
orbitals exist in nature or have been made artificially. Suggest a minimum atomic
number for such an element.
(Total 4 marks)
35. State the full electron configuration of U2+.
36. Consider how the shape of the Periodic Table is related to the three-dimensional
world we live in.
(a) How many 3p and 3d orbitals would there be if there were only the x and y
dimensions?
(b) How many groups in the p and d block would there be in such a two-dimensional
world?
37. The electron configuration of chromium can be expressed as [Ar]4sx3dy.
(i)
Explain what the square brackets around argon, [Ar], represent.
(ii)
State the values of x and y.
x: ..................................................................................................................................
y: ..................................................................................................................................
(iii) Annotate the diagram below showing the 4s and 3d orbitals for a chromium
atom using an arrow, and , to represent a spinning electron.
4s
3d
(Total 3 marks)
38. The electron configuration of chromium can be expresses as [Ar]4sx3dy.
(a) Explain what the square brackets around argon, [Ar], represent. (1)
(b) State the values of x and y. (1)
(c) Annotate the diagram below showing the 4s and 3d orbitals for a
chromium atom using an arrow up and down to represent a spinning
electron.
(Total 6 marks)
39. The graph below represents the energy needed to remove nine
electrons, one at a time, from an atom of an element. Not all of the electrons have
been removed.
Which element could this be and why?
a.
b.
c.
d.
C
Si
P
S
(Total 2 marks)
40. The graph below represents the successive ionization energies of sodium. The
vertical axis plots log (ionization energy) instead of ionization energy to allow the
data to be represented without using an unreasonably long vertical axis.
State the full electron configuration of sodium and explain how the successive
ionization energy data for sodium are related to its electron configuration.
(Total 3 marks)