Practice Questions
Practice Questions
1. An element consists of three isotopes in the relative abundance given below. What is the atomic mass of this element?
30.00% = 40.00 amu
50.00% = 41.00 amu
20.00% = 42.00 amu
(A) 40.90
(B) 41.00
(C) 41.90
(D) 42.20
(E) 42.90
2. The total number of electrons that can be accommodated in the fourth principal energy level is _____
(A) 2
(B) 8
(C) 18
(D) 32
(E) 50
3. If the set of quantum numbers n = 3, l = 1, ml = 0, ms = ±1/2 represents the last electron to be added to complete the ground state electron configuration of an element, which one of the following could be the symbol for the element?
(A) Na
(B) Si
(C) Th
(D) V
(E) Zn
4. Which element has the following electron configuration?
(A) Cr
(B) Mn
(C) Mo
(D) S
(E) Se
5. Complete the balanced equation below. The missing term is
6. Oxygen-15 has a half-life of 9.98 minutes. How much of a 20.0 g sample of oxygen-15 remains after 60.0 minutes?
(A) 0.156 g
(B) 0.312 g
(C) 0.625 g
(D) 1.25 g
(E) 2.50 g
7. Which of the following atoms would have the largest second ionization energy?
(A) Mg
(B) Cl
(C) S
(D) Ca
(E) Na
Statement I Statement II
8. Hydrogen has a lower ionization energy than does helium.   BECAUSE   Hydrogen bonds with halogens to form polar covalent bonds.
9. Order the elements S, Cl, and F in terms of increasing atomic radii.
(A) S, Cl, F
(B) Cl, F, S
(C) F, S, Cl
(D) F, Cl, S
(E) S, F, Cl
Statement I Statement II
10. The second ionization energy of B is higher than that of Be.   BECAUSE   The second electron to be removed from B and Be comes from the same principal energy level.
11. Oxygen has a smaller first ionization energy than fluorine.   BECAUSE   Oxygen has a higher Zeff value than does fluorine.
12. Removing an electron from sodium is an _____ process and removing an electron from fluorine is an _____ process.
(A) Endothermic, exothermic
(B) Exothermic, endothermic
(C) Endothermic, endothermic
(D) Exothermic, exothermic
(E) More information is needed
13. Which numbered response lists all the molecules below that exhibit resonance and none that do not?
  I. AsF5
(A) I only
(B) II only
(C) II and III
(D) III and IV
(E) I, II, and III
14. The sulfur hexafluoride molecule is nonpolar and contains no lone (unshared) electron pairs on the sulfur atom. Which answer choice lists all of the bond angles contained in sulfur hexafluoride?
(A) 120º
(B) 180º
(C) 90º and 180º
(D) 90º, 120º, and 180º
(E) 109.5º
Statement I Statement II
15. Molecules that contain a polar bond are not necessarily polar compounds.   BECAUSE   If polar bonds in a molecule are symmetrically arranged, then their polarities will cancel and they will be nonpolar.
16. The NH3 molecule is more polar than the NF3 molecule.   BECAUSE   Fluorine atoms are larger than hydrogen atoms.
17. Which one of the following molecules is octahedral?
(A) BeCl2
(B) SeF6
(C) BF3
(D) PF5
(E) CF4
18. Which molecule is incorrectly matched with the molecular geometry?
Molecule Molecular geometry
(A) SF6 octahedral
(B) CH4 tetrahedral
(C) SO3 trigonal planar
(D) SeCl4 tetrahedral
(E) PH3 trigonal pyramidal
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