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Atomic Structure

Examples of
Multiple Choice Questions

Which of the following has a positive charge?
(a) proton
(b) neutron
(c) anion
(d) electron
(e) atom

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.

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.

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.

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

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%

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

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

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

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.

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.

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

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

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

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

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

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

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

How many p electrons are there in an atom of rubidium?
(a) 12
(b) 18
(c) 24
(d) 9
(e) 6

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.


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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 Fundamentals of Chemistry | Chemical Formulas & Composition Stoichiometry | Chemical Equations & Rxn Stoichiometry | Types of Chemical Reactions |
| Atomic Structure | Chemical Periodicity | Chemical Bonding | Molecular Structure/Covalent Bonding Theories| Molecular Orbital Theory |
| Acids/Bases/Salts - Theory & Rxns | Acids/Bases/Salts - Calculations (including balancing redox rxns) | Gases | Solids & Liquids | Solutions |
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| Aqueous Equilibrium - Slightly Soluble Salts | Electrochemistry | Metallurgy | Metal Properties & Rxns | Nonmetals & Metalloids |
| Coordination Compounds | Nuclear Chemistry | Organic Chem - Formulas/Names/Properties | Organic Chem - Shapes/Rxns/Biopolymers |

To report any corrections, please e-mail Dr. Wendy Keeney-Kennicutt.