Download Multiple choice questions

D
− Electrons fill shells and subshells of lowest energy
first. The order of filling is:
1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d
• The ground state electron configuration of an atom
refers to electrons in their lowest energy level. Any
other configurations represent the atom in an excited
state and in a higher energy level.
5.
Multiple choice questions
6.
1. Which of the following is incorrect?
A Ernest Rutherford was famous for his ‘gold-foil’
experiment.
B The cathode-ray tube was the basis of
much experimental evidence for the initial
development of modern atomic theory.
C Pierre and Marie Curie were the first scientists
to discover radioactivity.
D The idea of atoms was proposed as far back as
400 BC by Democritus.
2. Which of the following ideas of John Dalton’s atomic
theory is no longer true?
A All matter is composed of tiny indestructible
particles called atoms.
B Atoms of the same element are alike in every
way.
C Atoms of different elements are different.
D Atoms can combine together in small numbers
to form molecules.
3. J. J. Thomson’s basis for the ‘plum-pudding’ model
for atomic structure was that:
A he discovered electrons by investigating
cathode rays in a specially designed cathoderay tube
B he found that cathode rays travelled towards
the positively charged anode, so the particles in
the rays must be negatively charged
C he measured the amount of deflection of
cathode rays attracted by a positively charged
plate
D he postulated that an atom consists of a core
of positive charges surrounded by negatively
charged electrons.
4. Ernest Rutherford discovered a nucleus in atoms.
What experimental evidence did he have?
A Alpha particles were bombarded at the atoms
of a thin gold foil.
B Most of the alpha particles passed directly
through the foil because gold atoms were
mainly made of empty space.
C A small number of alpha particles bounced
back because they hit the centre of the atom
which was made up of a core of negatively
charged particles.
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UNIT 1 The big ideas of chemistry
7.
8.
9.
10.
He proposed the nuclear model of the atom,
which suggested that the atom has a small
central core of protons surrounded by electrons
orbiting around it.
Which of the following particle pairs has
approximately the same mass?
A a proton and an electron
B a proton and a neutron
C a neutron and an electron
D an electron and a hydrogen atom
Three atoms, I, II and III, each have an atomic
number of 12. Atom I has 12 neutrons, atom II has
13 neutrons and atom III has 14 neutrons. Which of
the following sentences is correct?
A Atoms I, II and III are allotropes of each other.
B Atoms I, II and III are isotopes of the same
element.
C Atom I is a neutral atom while atoms II and III
are cations of atom I.
D Atom I is a neutral atom while atoms II and III
are anions of atom I.
A neutral atom of the isotope 136 C would consist of:
A 6 protons, 13 neutrons, 13 electrons
B 0 protons, 13 neutrons, 13 electrons
C 13 protons, 7 neutrons, 13 electrons
D 6 protons, 7 neutrons, 6 electrons.
Which of the following features is not present in a
mass spectrometer?
A The gas sample is bombarded by alpha
particles.
B The gas sample is ionised into positively
charged particles.
C The positive ions are accelerated by an electric
field.
D A magnetic field forces the particles to separate
in curved paths according to their mass-tocharge ratio.
Which of the following statements regarding
subatomic particles is correct?
A Protons are positively charged particles and
neutrons are negatively charged.
B The relative masses of an electron, a proton and
a neutron are all about 1 unit.
C In a neutral atom, the number of neutrons is
equal to the number of protons.
D Isotopes of an element have the same number of
protons but a different number of neutrons.
Bohr’s theory of the atom proposed that:
A electrons orbit the nucleus like planets move
around the sun
B no more than two electrons are allowed in any
energy level
C electrons move around the nucleus in fixed
orbits, each of which has a different energy level
D energy shells have subshells which contain
regions of space called orbitals.
11. The maximum number of electrons that can be
placed in the shell n = 3 is:
A 18
C 2
B 8
D 32.
12. Which of these electron configurations represents
an atom in an excited energy state?
A 1s22s22p43s2
B 1s22s22p63s23p4
C 1s22s22p6
D 1s22s22p63s23p63d34s2
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13. The electron configuration of 17
C1– is:
2 2
6 2
5
1
A 1s 2s 2p 3s 3p 3d
B 1s22s22p63s23p44s2
C 1s22s22p63s23p6
D 1s22s22p63s23p43d14s1.
14. The electron configuration 1s22s22p63s23p6 represents which of the following ions?
A O2–
C Al3+
2–
B S
D Na+
15. The electron configuration of an atom X is
1s22s22p63s23p1. Which of the following formulae is
most likely to be a compound formed with X?
A XF2
B CaX
C XCl3
D MgX2
16. The ground state electron configuration of a neutral
atom with an atomic number of 19 is:
A 1s22s22p63s23p63d1
B 1s22s22p63s23p7
C 1s22s22p63s23p64s1
D 1s22s22p63s23p53d14s1.
Review questions
1. (a) What did the alchemists contribute to the
growth of chemistry?
(b) Would you consider the alchemists to be
scientists? Justify your answer.
2. Examine the points made by Dalton in his atomic
theory. Consider each statement, and record:
(a) whether or not each suggestion still holds
(b) which other scientists were able to contribute
to refining or changing each proposal, and in
what way
(c) our current understanding of each statement.
3. From the results of Rutherford’s ‘gold-foil’
experiment, he suggested that the protons of the
atoms in the metal must be concentrated in the
centre, or nucleus, of the atom, while the electrons
are outside the nucleus. If this experiment were
to be repeated, what results would have been
obtained if:
(a) Thomson’s ‘plum-pudding’ model was correct
(b) the electrons were concentrated in the nucleus
and the protons orbited the nucleus?
4. Complete the following table of the structural
properties of atoms.
Atomic
number
Element
(Z )
Atomic
Number of:
mass
Protons Neutrons Electrons
(A)
1
nickel
59
gold
28
197
osmium
76
190
silver
47
107
silicon
mercury
0
79
6
8
19
20
16
80
14
120
5. Oxygen consists of three isotopes: 16O, 17O and
18
O. Show how many different masses an oxygen
molecule, O2, can have.
6. Naturally-occurring chromium consists of the
following four isotopes:
4.31% 50Cr (relative isotopic mass 49.946)
83.76% 52Cr (relative isotopic mass 51.941)
9.55% 53Cr (relative isotopic mass 52.941)
2.38% 54Cr (relative isotopic mass 53.939).
(a) Calculate the relative atomic mass of
chromium.
(b) Explain the difference between ‘relative atomic
mass’ and ‘mass number’, selecting appropriate
data from the above list.
7. A sample of carbon is found to contain two isotopes
with relative isotopic masses of 12.00 and 13.00. If
the relative atomic mass of carbon is 12.01, calculate
the relative abundances of each of the isotopes.
8. Suppose that you are a research chemist and you
have just discovered a new element. How would
you identify its different isotopes and determine its
relative atomic mass?
9. Explain the difference between:
(a) a ‘shell’ and a ‘subshell’
(b) an atomic ‘orbit’ and an ‘orbital’.
10. What is the maximum number of electrons that
may be found in:
(a) a 3p subshell
(b) a 2s subshell
(c) a 4d subshell
(d) the third shell?
11. Write the electron configuration of each of the
following in their ground states:
(a) sodium atom
(b) nitrogen atom
(c) argon atom
(d) iron atom
(e) copper atom
(f) calcium ion
(g) chloride ion.
CHAPTER 2 The atomic theory of matter
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