Download Ch. 6 Electric Structure HW

Ch. 6 Electronic Structure
1) What is the frequency of light that has a wavelength of 249 nm?
2) What is the energy of one photon of light with a wavelength of 445 nm?
3) In the photoelectric effect, KE = E(photon) – E(threshold). Remember E = hv, when it’s the
energy of a wave. Use the data in the table for when a sample of cesium was exposed to various
energies of light.
Light energy (eV)
3.87
3.88
3.89
3.90
3.91
Electron emitted? No
No
Yes
Yes
Yes
KE electron (eV)
----0
0.01
0.02
3A) What is the threshold frequency of cesium?
3B) A ray of violet light has a wavelength of about 4.2 x 10-7m. Will exposure to violet
light cause electrons to be emitted from cesium?
3C) What is the kinetic energy of the emitted electrons when cesium is exposed to UV
rays of frequency 1.3 x 1015Hz? (Hint: Hz = 1/sec)
4) Reference Figures 6.6, 6.11, and 6.12 in your textbook.
4A) What is the meaning of the term “quantum”?
4B) How is Plank’s constant related to Figure 6.6?
4C) What is a photon?
4D) What does each colored line in Hydrogen’s Line Spectrum represent?
4E) In what way is the Bohr model of the H atom more like steps than a ramp?
5) Particle Wave Duality
5A) Do you think the formation of a rainbow is more a demonstration of wave or
particle behavior of light? (Hint: P. 219)
5B) Describe a particle-like characteristic of light.
5C) Describe a particle like characteristic of an electron. (Hint: Think back to Ch. 2)
5D) According to De Broglie’s Theory, why would an electron show more wave-like
properties than a golf ball?
5E) Describe how the wave properties of the electron were demonstrated
experimentally after De Broglie’s theory was published.
6) Heisenberg’s Uncertainty Principle: Read your textbook, and go on you tube to watch videos
about his uncertainty principle.
6A) A 2 slit diffraction experiment shows how light can be treated as particles and how
light waves carry the statistical information for the experiment. If the same experiment were to use a
beam of electrons instead of light, would the results differ? Why or why not?
6B) If electrons were used in the 2 slit experiment instead of light, what change would
need to be made to the slit spacing in order to see a diffraction pattern?
7) Schrodinger Equation and Wave Functions
7A) Sketch each an S, p, and d orbital. (the shape of each)
7b) Re-write each that is true:
a) The 3p orbitals have 2 nodes.
b) The probability of finding an electron at the center of a d orbital is greater
than zero.
c) The probability of finding an electron at the center of a p orbital is zero.
d) The 4f orbital has 3 nodes.
e) The 2s orbital does not have any nodes.
represent?
7c) Look at Figure 6.19 in your textbook. What does the shaded region of each graph
7d) Based on Figure 6.19 in your textbook, how many nodes would you expect a 4s
orbital to have?
8) What is the maximum number of electrons that can be found in the 4f subshell?
9) What element is represented by the following electron configuration? [Ar]4s23d3
10) Orbital diagrams are a way of describing the organization of electrons, similar to electron
configurations.
10A) Make an orbital diagram for boron.
10B) Make an orbital diagram for Sc.
10C) Write the electron configuration of As.
11)Scientists can analyze metals using the emission spectrum produced when the sample is
introduced into the flame of an emission spectrometer. The flame provides the energy to excite
the electrons of the metal atoms to higher energy states. When the electrons return to the
ground state, lines of characteristic wavelengths are produced. The lines in the emission
spectrum are characteristic of the metal because each atom’s ground state electron
configuration is unique.
11A) The emission line used for zinc determinations in atomic emission spectroscopy is
214 nm. If there are 3.50 x 10^10 atoms of Zn emitting light in the instrument flame at any given
instant, what energy must the flame continuously supply to achieve this level of emission?
11B) Which of the following are valid transitions that produce lines in the emission
spectrum of Zn?
a) [Ar]4s23d10[Ar]4s23d104p2
b) [Ar]4s23d10[Ar]4s13d106s1
c) [Ar]3d10 [Ar]4s23d10
d) [Ar]4s23d10 [Ar]4s13d11
e) [Ar]4s13d106s1[Ar]4s23d10
12)Electron Configurations
12A) What is the electron configuration of Si?
12B) What is the electron configuration of Li?
12C) What is the electron configuration of Cu? (Hint: what should it be based on normal
patterns? Cu is an exception … you will learn about this exception in Ch. 7 … you could write the
exception if you prefer).
13)What is the valence electron configuration of the Group 2A element?
a) ns2np6
b) ns2np4
c) ns2
d) ns1