 | Atomic Structure
Examples of Multiple Choice Questions
|
- 1.
- Which of the following has a positive charge?
- (a) proton
- (b) neutron
- (c) anion
- (d) electron
- (e) atom
- 2.
- Rutherford
carried out experiments in which a beam of alpha particles was directed
at a thin piece of metal foil. From these experiments he concluded
that:
- (a) electrons are massive particles.
- (b) the positively charged parts of atoms are moving about with a velocity approaching the speed of light.
- (c) the positively charged parts of atoms are extremely small and extremely heavy particles.
- (d) the diameter of an electron is approximately equal to that of the nucleus.
- (e) electrons travel in circular orbits around the nucleus.
- 3.
- Consider the species 72Zn, 75As and 74Ge. These species have:
- (a) the same number of electrons.
- (b) the same number of protons.
- (c) the same number of neutrons.
- (d) the same number of protons and neutrons.
- (e) the same mass number.
- 4.
- The neutral atoms of all of the isotopes of the same element have
- (a) different numbers of protons.
- (b) equal numbers of neutrons.
- (c) the same number of electrons.
- (d) the same mass numbers.
- (e) the same masses.
- 5.
- What is
the atomic weight of a hypothetical element consisting of two isotopes,
one with mass = 64.23 amu (26.0%), and one with mass = 65.32 amu?
- (a) 65.3 amu
- (b) 64.4 amu
- (c) 64.9 amu
- (d) 65.0 amu
- (e) 64.8 amu
- 6.
- Naturally
occurring rubidium consists of just two isotopes. One of the isotopes
consists of atoms having a mass of 84.912 amu; the other of 86.901 amu.
What is the percent natural abundance of the heavier isotope?
- (a) 15%
- (b) 28%
- (c) 37%
- (d) 72%
- (e) 85%
- 7.
- What is the frequency of light having a wavelength of 4.50 x 10-6 cm?
- (a) 2.84 x 10-12 s-1
- (b) 2.10 x 104 s-1
- (c) 4.29 x 1014 s-1
- (d) 1.06 x 1022 s-1
- (e) 6.67 x 1015 s-1
- 8.
- The emission spectrum of gold shows a line of wavelength 2.676 x 10-7 m. How much energy is emitted as the excited electron falls to the lower energy level?
- (a) 7.43 x 10-19 J
- (b) 5.30 x 10-20 J
- (c) 6.05 x 10-19 J
- (d) 3.60 x 10-20 J
- (e) 5.16 x 10-20 J
- 9.
- Which of the responses contains all the statements that are consistent with the Bohr theory of the atom (and no others)?
- (1) An electron can remain in a particular orbit as long as it continually absorbs radiation of a definite frequency.
- (2) The lowest energy orbits are those closest to the nucleus.
- (3) An electron can jump from the K shell (n = 1 major energy
level) to the M shell (n = 3 major energy level) by emitting radiation
of a definite frequency.
- (a) 1,2,3
- (b) 2 only
- (c) 3 only
- (d) 1,2
- (e) 2,3
- 10.
- The Heisenberg Principle states that _____________.
- (a) no two electrons in the same atom can have the same set of four quantum numbers.
- (b) two atoms of the same element must have the same number of protons.
- (c) it is impossible to determine accurately both the position and momentum of an electron simultaneously.
- (d) electrons of atoms in their ground states enter
energetically equivalent sets of orbitals singly before they pair up in
any orbital of the set.
- (e) charged atoms (ions) must generate a magnetic field when they are in motion.
- 11.
- Which statement about the four quantum numbers which describe electrons in atoms is incorrect?
- (a) n = principal quantum number, n = 1, 2, 3, ......
- (b) l = subsidiary (or azimuthal) quantum number, l = 1, 2, 3, ... , (n+1)
- (c) ml = magnetic quantum number, ml = (-l), .... , 0, .... , (+l)
- (d) ms = spin quantum number, ms = +1/2 or -1/2.
- (e) The magnetic quantum number is related to the orientation of atomic orbitals in space.
- 12.
- Which atomic orbital is spherical in shape? (Note: you should know and be able to recognize the shapes of the s orbital, px, py, and pz orbitals, and dxy, dyz, dxz, dx2-y2 and dz2 orbitals.)
- (a) 2s
- (b) 3p
- (c) 3d
- (d) 4f
- (e) they are all spherical
- 13.
- The maximum number of electrons that can be accommodated in a sublevel for which l = 3 is:
- (a) 2
- (b) 10
- (c) 6
- (d) 14
- (e) 8
- 14.
- The ground state electron configuration for arsenic is:
- (a) [Ar] 4s2 4p13
- (b) [Kr] 4s2 4p1
- (c) 1s2 2s2 2p6 3s2 3p6 3d12 4s2 4p1
- (d) 1s2 2s2 2p6 3s2 3p6 4s2 3d8 4p5
- (e) 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p3
- 15.
- Which of the following electron configurations is correct for nickel?
- (a) [Ar] 4s1 3d8
- (b) [Kr] 4s1 4d8
- (c) [Kr] 4s1 3d8
- (d) [Kr] 4s2 3d8
- (e) [Ar] 4s2 3d8
- 16.
- The outer electronic configuration ns2np4 corresponds to which one of the following elements in its ground state?
- (a) As
- (b) Ca
- (c) Cr
- (d) Br
- (e) S
- 17.
- In the ground state of a cobalt atom there are _____ unpaired electrons and the atom is _____.
- (a) 3, paramagnetic
- (b) 5, paramagnetic
- (c) 2, diamagnetic
- (d) 0, diamagnetic
- (e) 2, paramagnetic
- 18.
- Which one of the following sets of quantum numbers could be those of the distinguishing (last) electron of Mo?
- (a) n = 4, l = 0, ml = 0, ms = +1/2
- (b) n = 5, l = 1, ml = 9, ms = -1/2
- (c) n = 4, l = 2, ml = -1, ms = +1/2
- (d) n = 5, l = 2, ml = +2, ms = -1/2
- (e) n = 3, l = 2, ml = 0, ms = +1/2
- 19.
- How many p electrons are there in an atom of rubidium?
- (a) 12
- (b) 18
- (c) 24
- (d) 9
- (e) 6
- 20.
- A
neutral atom of an element has 2 electrons in the first energy level, 8
in the second energy level and 8 in the third energy level. This
information does not necessarily tell us:
- (a) the atomic number of the element.
- (b) anything about the element's chemical properties.
- (c) the total number of electrons in s orbitals.
- (d) the total number of electrons in p orbitals.
- (e) the number of neutrons in the nucleus of an atom of the element.
Answers:
1. (a) 2. (c) 3. (c) 4. (c) 5. (d) 6. (b) 7. (e) 8. (a) 9. (b) 10. (c) 11. (b) 12. (a) 13. (d) 14. (e) 15. (e) 16. (e) 17. (a) 18. (c) 19. (b) 20. (e)

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