Chemistry Exam

 

  1. A molecule with the formula AB3 has one lone pair on atom A. What is the hybridization of atom A? Which element could atom A be?
  2. Methionine is shown below. What is the hybridization on each C, O, N, and S? How many total pi bonds are in this molecule?
  3. Draw the Lewis structure(s) of the phosphate polyatomic ion. Indicate the hybridization on the P atom. Also, indicate what the phosphorus-oxygen bond order is.
  4. Analysis of a compound indicates that it contains 77.55% Xe and 22.45% F by mass.
    1. What is the empirical formula of this compound?
    2. If you assume that the empirical formula is the same as the molecular formula, write a Lewis structure for the compound.
    3. Predict the shape of this molecule.
    4. What is the hybridization on the central atom?
  5. Draw the Lewis structure(s) of HNO2. What is the hybridization on all atoms besides H?
  6. a) Write the molecular electron configuration for each molecule; b) determine the bond order of each molecule; c) determine which molecule will have the shortest bond; and d) determine which molecule(s) if any are paramagnetic.
  7. H2, H2+, and H2

ii. O2, O2+, and O2

iii. N2, N2+, and N2

  1. Explain why N22+ is diamagnetic and O24+ is paramagnetic even though they both have the same number of valence electrons.
  1. Rank the following bonds in order of increasing polarity: C-Br, C-Cl, C-F, and C-H.
  2. Draw the Lewis structure(s) of the following molecules. Include resonance structures if they exist.
    1. CO32-
    2. IF5
    3. CH3Br
  3. 6 points: Let us consider Zn:
    1. What is the electron configuration of Zn?
    2. What is the electron configuration of Zn2+?
  4. For the molecules whose Lewis structures are given below,
    1. Label the molecule as polar or non-polar, and show the direction of the net (molecular) dipole moment if one exists.
    2. Indicate the electron domain geometry and the molecular geometry of the central atom.
  5. Image result for ch2cl2

ii. Image result for clf3

  1. a. Draw the Lewis structure(s) of SO2.

b. What is the bond order of the SO bond based off your Lewis structure.

  1. A molecule AB3, where A and B represent two different atoms, has polar bonds and is nonpolar. What molecular geometry must this molecule be? What atom could atom A be?
  2. Draw the complete Lewis structure including resonance if applicable for OCN. Show the formal charge on each atom.
  3. Rank the following in terms of atomic radii from smallest to largest and provide a brief explanation:
    1. Li, K, and Na

________ < ________ < ________

(smallest) (largest)

Explain:

    1. Ca2+, Ar, and Cl

________ < ________ < ________

(smallest) (largest)

Explain:

  1. Let us think about first and second ionization energies.
    1. Does potassium (K) or calcium (Ca) have a higher first ionization energy (no explanation needed)?
  2. Describe why the second ionization energy of potassium (K) is much greater than the second ionization energy of calcium (Ca). Hint: think about electron configurations.
  3. Let us consider the element oxygen, O:
    1. How many valence electrons does O have? ________________
    2. How many core electrons does O have? _______________
    3. Below are various orbital diagrams of O. Circle the orbital diagram(s) below that are valid electron arrangements in the lowest energy state. In the space below, provide a brief explanation as to why certain orbital diagram(s) may be invalid.
      1. _______ _______ _______ _______ _______

1s 2s 2p

      1. _______ _______ _______ _______ _______

1s 2s 2p

      1. _______ _______ _______ _______ _______

1s 2s 2p

Explain why certain orbital(s) above are invalid:

  1. 6 points: Circle the radiation that corresponds to a higher energy in each pair (i.e. – circle one it­­­em in each row):

IR radiation

Gamma rays

Absorption of an electron in the hydrogen atom from n=1 to n=3

Absorption of an electron in the hydrogen atom from n=2 to n=4

Red light emitted

Blue light emitted

  1. Answer the following questions:
      1. Sketch a p orbital. How do the three p orbitals in a subshell differ from one another?
      2. Can the electron occupying the orbital be outside of the region of space you have just sketched? Explain.
  2. Given the atoms Br, O, Rb, and S:
    1. Which has the highest ionization energy?
    2. Which has the largest atomic radius?
  3. What is the condensed electron configuration for phosphorus (P) in the ground state? How many valence electrons does P have?
  4. Give the four quantum numbers of the valence electrons present in Zr2+. ***There is more than one correct answer!
  5. Perform the following conversions:
    1. 2.50 x 10-22 J into Hz
    2. 276 nm into J
    3. 400.0 MHz into J
    4. 225 GHz into nm
  6. The quantum numbers of Planet X are exactly like ours, except ml takes on the values of -2l to +2l in steps of 1 Sketch the periodic table is it would appear on Planet X through element 52. How many electrons are in each subshell (s, p, d, and f)? What is the atomic number of the first element with an electron in a d orbital? THIS IS A VERY HARD PROBLEM AND NOTHING THIS HARD WILL BE ON THE TEST!
  7. For the H-atom, calculate the following:
    1. ΔE in J for the n=1 to n=2 transition.
    2. Λ in nm for the n=2 to n=3 transition.
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