Chapter 4

Homework 4.1

1. What was the major shortcoming of Rutherford's model of the atom?

2. Write and label the equation that relates the speed, wavelength, and frequency of electromagnetic radiation.

3. a) List five examples of electromagnetic radiation, other than visible light and its forms.
b) What is the speed of all forms of electromagnetic radiation in a vacuum?
c) Relate the frequency and wavelength of any form of electromagnetic radiation.

4. What are the frequency and wavelength ranges of visible light?

5. List the colors of light in the visible spectrum in order of increasing frequency.

Homework 4.2

1. Define the following:
a) electromagnetic radiation;
b) wavelength;
c) frequency;
d) quantum;
e) photon

2. What is meant by the dual wave-particles nature of light?

Homework 4.3

1. Describe the Bohr model of the hydrogen atom.

2. a) How are the wavelength and frequency of electromagnetic radiation related?
b) How are the energy and frequency of electromagnetic radiation related?
c) How are the energy and wavelength of electromagnetic radiation related?

3. Distinguish between the ground state and an excited state of an atom.

4. According to the Bohr model of the hydrogen atom, how is hydrogen's emission spectrum produced?

5. Determine the frequency of light with a wavelength of 4.257 x 10-7 cm.

6. Determine the energy in joules of a photon whose frequency is 3.55 x 1017 Hz.

7. a) Which has a longer wavelength, green or yellow light?
b) Which has a higher frequency, an X ray or a microwave?
c) Which travels at a greater speed, ultraviolet or infrared light?

Homework 4.4

1. Define the following:
a) main energy level;
b) quantum numbers

2. a) List the four quantum numbers.
b) What general information about atomic orbitals is provided by the quantum numbers?

3. Describe briefly what specific information is given by each of the four quantum numbers and indicate the symbol for each.

4. How many electrons could be contained in the following main energy levels with n equal to:
a) 1
b) 3
c) 4
d) 6
e) 7

5. a) What is an orbital?
b) Describe an orbital in terms of an electron cloud.

Homework 4.5

1. a) What is an atom's electron configuration?
b) What three principles guide the electron configuration of an atom?

2. Identify the elements having the following electron configurations:
a) 1s2 2s2 2p6 3s2 3p3

3. a) Give the statement of Hund's Rule.
b) What is the basis for this rule?

4. a) Give the statement of Pauli's Exclusion Principle.
b) What is the significance of the spin quantum number?
c) Compare the values of the spin quantum number for two electrons in the same orbital.

5. Write the orbital notation for the following elements (think about what you need to show before you attempt the orbital notation):
a) P
b) B
c) Na
d) C

6. Write the electron configuration notation for an unidentified element that contains the following number of electrons:
a) 3
b) 6
c) 8
d) 13

Homework 4.6

1. What three methods are used to represent the arrangement of electrons in atoms?

2. a) What is an octet of electrons?
b) Which elements contain an octet of electrons?

3. Write the complete electron configuration notation, the noble gas notation, and the orbital notation for the following elements:
a) carbon
b) neon
c) sulfur

4. Identify the elements having the following electron configurations:
a) [Ar] 4s1
b) contains four electrons in its third and outer main energy level
c) contains one paired and three unpaired electrons in its fourth and outer main energy level.

5. a) What is meant by the highest occupied energy level in an atom?
b) What are inner shell electrons?

6. Determine the highest occupied energy level in the following elements:
a) He
b) Be
c) Al
d) Ca
e) Sn

7. Given that the electron configuration for oxygen is 1s2 2s2 2p4, answer the following questions:
a) How many electrons are in each atom?
b) What is the atomic number of this element?
c) Write the orbital notation for oxygen's electron configuration.
d) How many unpaired electrons does oxygen have?
e) What is the highest occupied energy level?
f) How many inner shell electrons does the atom contain?
g) In which orbital(s) are these inner shell electrons located?

8. a) What are the noble gases?
b) What is a noble gas configuration?
c) How does noble gas notation simplify writing an atom's electron configuration?

9. Write the noble gas notation for the electron configuration of each of the elements that follow:
a) Cl
b) Ca
c) Se

10. Write both the complete electron configuration notation and the noble gas notation for each of the following elements:
a) Na
b) Sr
c) P

11. Identify each of the following atoms on the basis of its electron configuration:
a) 1s2 2s2 2p1
b) 1s2 2s2 2p5
c) [Ne] 3s2
d) [Ne] 3s2 3p2
e) [Ne] 3s2 3p5
f) [Ar] 4s1
g) [Ar] 4s2 3d6