SL Topic 2 : Atomic structure
For each question choose the answer you consider to be the best.
1. Which is the correct definition of the atomic number of an atom?
A. The total number of neutrons and protons in the nucleus of an atom
B. The total number of neutrons, protons and electrons in an atom
C. The number of electrons in the outer energy level of an atom
D. The number of protons in the nucleus of an atom
2. What is the symbol for a species that contains 8 protons, 9 neutrons and 10 electrons?
A.
17 3N
8
B.
17 F
9
C.
17 F
8
D.
17 2O
8
3. How many protons, neutrons and electrons are present in an atom of 40Ar?
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4. Which statement about isotopes is correct?
A. Isotopes have the same molecular formula but a different structural formula.
B. Isotopes have the same number of neutrons in atoms of the element
C. Isotopes of atoms of the same element have the same electron configuration.
D. Isotopes of atoms of the same element have the same mass number.
5. Which species represents a pair of isotopes?
species
number of protons
number of neutrons
number of electrons
W
15
15
15
X
16
16
18
Y
16
16
16
Z
15
16
15
A. W and X
B. X and Y
C. X and Z
D. W and Z
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6. An atom of thorium has a mass number of 234. Which is correct concerning the atomic
number for this isotope and the number of neutrons in its nucleus?
7. What is the difference between the two neutral atoms 239
Np and
93
239
Pu
94
?
A. The number of protons, neutrons and electrons
B. The number of protons and electrons only
C. The number of protons and neutrons only
D. The number of neutrons only
8. What is the number of electrons in one 40
Ca2+ ion?
20
A. 40
B. 20
C. 22
D. 18
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9. The relative atomic mass of bromine is 79.9. It consists of two isotopes 79Br and
What is the percentage of 81Br in a sample of naturally occurring bromine?
81
Br.
A. 40%
B. 45%
C. 50%
D. 55%
10. The two isotopic abundances of element Z are 90% of
What is the relative atomic mass of Z?
39
Z
19
and 10% of
40
Z.
19
A. 39.10
B. 39.90
C. –39.50
D. 19
11. Which is correct for the mass and charge of the sub-atomic particle concerned?
A.
B.
C.
D.
Particle
Electron
Proton
Electron
Proton
Mass / amu
1
1
0
0
Relative charge
0
–1
–1
+1
12. In what order do the orbitals increase in energy within the same level?
A. d < f < p < s
B. f < d < p < s
C. s < p < d < f
D. s < d < p < f
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13. An element shows three peaks in its mass spectrum below.
What is the relative atomic mass of the element?
A. 23.0
B. 24.6
C. 25.0
D. 25.7
14. Which ion will be deflected the most in a mass spectrometer?
A.
12 +
B.
13 +
C.
12 2+
D.
13 2+
C
C
C
C
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15. Which atoms have one or more unpaired electrons in their ground state?
I. Copper
II. Chromium
III. Zinc
A. I and II only
B. I andIII only
C. II and III only
D. I, II and III
16. Which is correct about the infrared and ultraviolet regions of the spectrum?
17. Which process produces the first line in the visible region of the
electromagnetic spectrum for the emission spectrum of hydrogen?
A. The absorption of energy by electrons
B. The release of energy by electrons
C. The deflection of energy by electrons
D. The convergence of energy by electrons
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18. Which are correct for the hydrogen emission spectrum?
I.
The spectrum consists of lines converging at higher energy.
II. The lines in the UV region are due to electronic transitions to the lowest
energy level.
III. The lines are due to electrons absorbing energy as they move from
higher energy levels to lower energy levels.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
19. What is the electron configuration of an S2- ion?
A. 1s22s22p4
B. 1s22s22p6
C. 1s22s22p63s23p6
D. 1s22s22p2
20. Which all contain the same electron arrangement?
A. O2-, Ne, Cl+
B. Ca+, K+, Ar
C. O2+, F+, Ne
D. Al3+, Na+, Mg2+
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