Ch. 6 & 7  atomic structure & periodic trends             test     [100 points]     AP Chem

For problems involving calculations, show your work in an organized manner, include any relevant equation (or formula and conversion factor(s)), put the proper units in your calculations / answer, and have the proper number of significant figures in your answer.              

Academic Honesty:   The answers on this test are my own and I am using only the allowed set of notes as described in the syllabus.  I have not discussed the test questions with anyone before or during the test nor have I seen the test questions prior to the exam.  If you violate any of the preceding items or do not sign, your semester grade is a F.

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1.  Light with a wavelength of 589 nm shone onto a metal caused the emission of electrons, whose kinetic energy is 1.4 * 10-19 J.  What is the minimum frequency needed for electron emission in this metal ?  [10 points]

2.   What is the ___ of the emitted light due to the transition of an electron in the hydrogen atom from n = 4 to n = 1 energy state ?  [15 points]

a.  energy

b.  frequency

c.  wavelength

3.  What are all possible set of quantum numbers for an electron in the 2p atomic orbital ?  Briefly, describe what aspect of an atomic orbital that corresponds to each quantum number.  [10 points]

4.  Sketch ___ atomic orbital; include the x-, y-, z- axis to show the relationship between these axis and the atomic orbital.  [10 points]

a.  px

b.  dxy

5.  sketch the orbital diagram of  ___; use the noble gas “shortcut” notation.  [10 points]

a.  oxygen

b.  arsenic

6.   What is the relative ____ between fluorine versus sulfur ?  Justify / rationalize your response.  [20 points]

a.  atomic size

b.  (first) ionization energy

7.   Write the chemical equation describing the first-, second-, and third- ionization energy for calcium.  [10 points]

8.  Justify / rationalize, for calcium:  2nd ionization energy  << 3rd ionization energy.  [10 points]

9.  old topic:  define “isotope” and provide 2 examples of (reasonable / potential) isotopes.  [5 points]

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Ch. 6 & 7  atomic structure & periodic trends             retest  [100 points]     AP Chem

1.  Light with a wavelength of 765 nm shone onto a metal caused the emission of electrons with a kinetic energy of 1.35 * 10-19 J.  What is the range of wavelength (in meters) needed for electron emission in this metal ?  [15 points]

2.  In certain situations in the photoelectric effect, the intensity of light does have an effect, while in other situations, the intensity of light has no effect – describe both of these situations.  [10 points]

3.  rationalize / justify the periodic trend in the (first) ionization energy:  [15 points]

a.  in general, it increases in a row (left to right)

b.  in general, it is relatively stable in the d-block.

c.  the exception involving phosphorus and sulfur.

 

4.   write the electron configuration of  __  (using nobel gas “shortcut”) and identify the valence and kernel electrons.  [10 points]

a.   lead

b.  strontium

5.   lab related questions:  justify / rationalize your response.  [10 points]

a.  Which is the better color, red or blue, to measure the absorption of a red-colored solution ?

b. based on the following hypothetical graph,

abs spectrum

              what would be the “best” wavelength to use ?

6.  electron spin.  [15 points]

a.  Define “electron spin”

b.  relevance to an electron orbital (with respect to the maximum number of electrons in an orbital)

c.  relevance to the magnetic properties of an atom ?

7.  Pick any 2 of the following choices:  describe ___.  Clearly identify your choice; will evaluate 2 lowest-scoring choices if you do all three choices.  [10 points] 

a. aufbau principle
b.  Pauli exclusion principle
c.  Hund’s rule

8.  old topics  [15 points]

a.  Describe the results of Rutherford’s experiment and its interpretation regarding the atom. 

b.  For the reaction, H2  +  O2   -->  H2 O, the  

rate  =  k [H2 ] [O2 ]1/2

if the rate is 2.5 μM / second, [H2 ] = 2.0 mM and [O2 ] = 5.0 mM, then what is the value and units of the rate constant, k ?