Atomic Structure Chemical Bonds Molecular Geometry by hcj


									                 Atomic Structure, Chemical Bonds, Molecular Geometry, Intermolecular Forces
                                                Practice Test

Questions 1-5: The set of lettered choices is a list of regions in the electromagnetic spectrum. Select
the one lettered choice that best fits each statement. A choice may be used once, more than once, or
not at all.

a) infrared            b) microwaves                 c) ultraviolet           d) visible      e) x-rays

1)   Radiation   in   this   region has the highest energy.
2)   Radiation   in   this   region is used to analyze colored solutions.
3)   Radiation   in   this   non-visible region passes through ordinary glass but can be blocked with treated glass.
4)   Radiation   in   this   region is used in the analysis of metallic crystal structures.
5)   Radiation   in   this   region is used as a detection beam across doorways and windows.

6) Which is a list of elements in order of increasing metallic character?
a) Si, P, S     b) As, P, N     c) Sr, Ca, Mg      d) Br, Se, As    e) Na, Ne, F

7) The electron configuration of the oxide ion is most similar to the electron configuration of the:
a) sulfide ion    b) nitride ion     c) oxygen atom       d) nitrogen atom        e) fluorine atom

8) Which describes the behavior of potassium metal during a chemical reaction?
         I.   Neutral atoms become ions with a 1+ charge
         II.  Neutral atoms take on protons
         III. Neutral atoms become ions with a corresponding increase in radius
a) I only            b) I and II only     c) III only   d) II and III only     e) I, III, and III

9) Which element has atoms with more valence electrons than core electrons?
a) Be       b) F     c) Na      d) P      e) Ar

10) What is the number of half-filled orbitals in an atom of chromium?
a) 0      b) 2      c) 4       d) 6        e) 12

11) Most members of the lanthanide series have the same number of
   a) 4s and 6s electrons, but different numbers of 4f electrons
   b) 4s and 6s electrons, but different numbers of 5s electrons
   c) 4f and 6s electrons, but different numbers of 5f electrons
   d) 4f and 5s electrons, but different numbers of 6s electrons
   e) 5s electrons, but different number of 6s and 4f electrons

12) How does a phosphorus atom differ from a phosphide ion?
          I.        The phosphide ion has more electrons
          II.       The phosphorus atom has more unpaired electrons
          III.      The phosphide ion has more kernel electrons
a) I only      b) I and II only   c) I and III only   d) II and III only                      e) I, II, and III

13) What is the number of electrons in an atom of scandium that have an l quantum number of 1?
a) 1     b) 3      c) 4     d) 6       e) 12

14) The electron configuration of atoms of element X is: [Ar]4s 23d10. Which is the most likely
formula for the compound of this element and oxygen?
a) XO      b) X2O      c) XO2      d) X2O3     e) X2O5

15) What is the number of filled orbitals in an atom of sulfur?
a) 1      b) 3      c) 4        d) 7       e) 8

16) Which lists species with the same electron configuration; that is, species that are isoelectric?
a) Mg, Ca, Sr      b) Mg2+, Ca2+, Sr2+     c) S2-, Cl-, K+    d) Fe, Co, Ni      e) F-, S2-, As3-
17) Which color in the visible spectrum is associated with the lowest frequency?
a) blue     b) green         c) red     d) violet     e) yellow

18) According to quantum mechanics, what is the maximum number of electrons that can occupy the fourth
energy level in a ground state atom?
a) 2      b) 4       c) 8       d) 16   e) 32

19) Which pair of atoms represents nuclei that have the same number of neutrons?
a) Co-56 and Co-58       b) Mn-57 and Fe-57       c) Ni-58 and Fe-57
d) Ni-58 and Co-57       e) Ni-59 and Fe-56

Questions     20-24 refer to the following descriptions of bonding in different types of solids.
       A)     Lattice of positive and negative ions held together by electrostatic forces
       B)     Closely packed lattice with delocalized electrons throughout
       C)     Strong single covalent bonds with weak intermolecular forces
       D)     Strong multiple covalent bonds (including pi bonds) with weak intermolecular forces
       E)     Macromolecules held together with strong polar bonds

20)   Cesium chloride, CsCl(s)
21)   Gold, Au(s)
22)   Carbon dioxide, CO2(s)
23)   Methane, CH4(s)

24) The melting point of MgO is higher than that of NaF. Explanations for this observation include
which of the following?
        I.    Mg2+ is more positively charged than Na+
        II.   O2- is more negatively charged than F-
        III.  The O2- ion is smaller than the F- ion
   a) II only b) I and II only         c) I and III only d) II and III only    e) I, II ,and III

25) Of the following molecules, which has the largest dipole moment?
   a) CO             b) CO2        c) O2          d) HF        e) F2

26) In which of the following processes are covalent bonds broken?
   a) I2(s)  I2(g)                 c) NaCl(s)  NaCl(l)       e) Fe(s)  Fe(l)
   b) CO2(s)  CO2(g)               d) C(diamond)  C(g)

27) Which of the following gases deviates most from ideal behavior?
   a) SO2             b) Ne        c) CH4        d) N2         e) H2

Questions 28-30 refer to the following diatomic species.
        a) Li2          b) B2           c) N2     d) O2            e) F2
28) Has the largest bond-dissociation energy
29) Has a bond order of 2
30) Contains 1 sigma and 2 pi bonds

31) In a molecule in which the central atom exhibits d 2sp3 hybrid orbitals, the electron pairs are
directed toward the corners of:
    a) a tetrahedron                c) a trigonal bipyramid       e) an octrahedron
    b) a square-based pyramid       d) a square

32) CH3CH2OH boils at 78°C and CH3OCH3 boils at -24°C, although both compounds have the same
composition. The difference in boiling points may be attributed to a difference in:
   a) molecular mass        c) specific heat             e) heat of combustion
   b) density               d) hydrogen bonding
CH3-CH2-CH2-CH2-CH3                        CH3-CH2-CH2-OH                 HO-CH2-CH2-OH
          X                                        Y                            Z
Based on the concepts of polarity and hydrogen bonding, which of the following sequences correctly
lists the compounds above in the order of their increasing solubility in water?
a) Z < Y < X         b) Y < Z < X          c) Y < X < Z          d) X <Z < Y          e) X < Y < Z

34) Molecules that have planar configurations include which of the following?
     I.   BCl3
     II.  CHCl3
     III. NCl3
a) I only            b) III only          c) I and II only      d) II and III only                e) I, II, and III

35) The electron-dot structure (Lewis structure) for which of the following molecules would have two
unshared pairs of electrons on the central atom?
   a) H2S             b) NH3                c) CH4               d) HCN               e) CO2

36) Which of the following molecules has a dipole moment of zero?
   a) C6H6 (benzene)        b) NO         c) SO2               d) NH3                             e) H2S

1) Account for the following in terms of models of atomic structure: Both the sulfide ion and the chloride ion have
18 electrons. However, the radius of the sulfide ion is greater.

2) Is the radius of Mg2+ greater than, equal to, or smaller than the radius of Mg? Explain.

Answer Key
   1) E                          30)   C
   2) D                          31)   E
   3) B                          32)   D
   4) E                          33)   E
   5) A                          34)   A
   6) D                          35)   A
   7) B                          36)   A
   8) A
   9) B
   10) D
   11) A
   12) B
   13) E
   14) A
   15) D
   16) C
   17) C
   18) E
   19) D
   20) A
   21) B
   22) D
   23) C
   24) B
   25) D
   26) D
   27) A
   28) C
   29) D

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