Chapter 2

Define the frequency of electromagnetic radiation. How is frequency related to wavelength?

What determines the color of light? Describe the difference between red light and blue light.

What determines the color of a colored object? Explain why grass appears green.

Give an approximate range of wavelengths for each type of electromagnetic radiation and summarize the characteristics and/or the uses of each. a. gamma rays b. X-rays c. ultraviolet radiation d. visible light e. infrared radiation f. microwave radiation g. radio waves

Explain the wave behavior known as interference. Explain the difference between constructive and destructive interference.

Describe the photoelectric effect. How did experimental observations of this phenomenon differ from the predictions of classical electromagnetic theory?

What is a photon? How is the energy of a photon related to its wavelength? Its frequency?

What is an emission spectrum? How does an emission spectrum of a gas in a discharge tube differ from a white light spectrum?

Describe the Bohr model for the atom. How did the Bohr model account for the emission spectra of atoms?

Explain Heisenberg"s uncertainty principle. What paradox is at least partially solved by the uncertainty principle?

What is a trajectory? What kind of information do you need to predict the trajectory of a particle?

Newton"s laws of motion are deterministic. Explain this statement.

An electron behaves in ways that are at least partially indeterminate. Explain this statement.

For each solution to the Schrodinger equation, which quantity can be precisely specified: the electron"s energy or its position? Explain.

What are the possible values of the principal quantum number n? What does the principal quantum number determine?

What are the possible values of the angular momentum quantum number l? What does the angular momentum quantum number determine?

What are the possible values of the magnetic quantum number ml? What does the magnetic quantum number determine?

Explain the difference between a plot showing the probability density for an orbital and one showing the radial distribution function.

List the four different sub levels. Given that only a maximum of two electrons can occupy an orbital, determine the maximum number of electrons that can exist in each sub level.

Why are atoms usually portrayed as spheres when most orbitals are not spherically shaped?

List these types of electromagnetic radiation in order of (i) increasing wavelength and (ii) increasing energy per photon: a. radio waves b. microwaves c. infrared radiation d. ultraviolet radiation

List these types of electromagnetic radiation in order of (i) increasing frequency and (ii) decreasing energy per photon: a. gamma rays b. radio waves c. microwaves d. visible light

Calculate the frequency of each wavelength of electromagnetic radiation: a. 632.8 nm (wavelength of red light from helium neon laser) b. 503 nm (wavelength of maximum solar radiation) c. 0.052 nm (wavelength contained in medical X rays)

Calculate the wavelength of each frequency of electromagnetic radiation: a. 100.2 MHz (typical frequency for FM radio broadcasting) b. 1070 kHz (typical frequency for AM radio broadcasting) (assume four significant figures) c. 835.6 MHz (common frequency used for cell phone communication)

A laser pulse with wavelength 532 nm contains 3.85 mJ of energy. How many photons are in the laser pulse?

Determine the energy of 1 mol of photons for each kind of light. (Assume three significant figures.) a. infrared radiation (1500 nm) b. visible light (500 nm) c. ultraviolet radiation (150 nm)

How much energy is contained in 1 mol of each? a. X-ray photons with a wavelength of 0.135 nm b. g-ray photons with a wavelength of 2.15 * 10-5 nm

A proton in a linear accelerator has a de Broglie wavelength of 122pm. What is the speed of the proton?

Calculate the de Broglie wavelength of a 143-g baseball traveling at 95 mph. Why is the wave nature of matter not important for a baseball?

A 0.22-caliber handgun fires a 27-g bullet at a velocity of 765 m>s. Calculate the de Broglie wavelength of the bullet. Is the wave nature of matter significant for bullets?

Which electron is, on average, closer to the nucleus: an electron in a 2s orbital or an electron in a 3s orbital?

Which electron is, on average, further from the nucleus: an electron in a 3p orbital or an electron in a 4p orbital?

What are the possible values of l for each given value of n? a. 1 b. 2 c. 3 d. 4

What are the possible values of ml for each given value of l? a. 0 b. 1 c. 2 d. 3

Which set of quantum numbers cannot occur together to specify an orbital? a. n = 2, l = 1, ml = -1 b. n = 3, l = 2, ml = 0 c. n = 3, l = 3, ml = 2 d. n = 4, l = 3, ml = 0

Sketch the 3d orbitals. How do the 4d orbitals differ from the 3d orbitals?

Determine whether each transition in the hydrogen atom corresponds to absorption or emission of energy. a. n = 3 - n = 1 b. n = 2 - n = 4 c. n = 4 - n = 3

According to the quantum-mechanical model for the hydrogen atom, which electron transition produces light with the longer wavelength: 2p - 1s or 3p - 1s?

According to the quantum-mechanical model for the hydrogen atom, which electron transition produces light with the longer wavelength: 4p - 2s or 4p - 3p?

Calculate the wavelength of the light emitted when an electron in a hydrogen atom makes each transition and indicate the region of the electromagnetic spectrum (infrared, visible, ultraviolet, etc.) where the light is found. a. n = 2 - n = 1 b. n = 3 - n = 1 c. n = 4 - n = 2 d. n = 5 - n = 2

Calculate the frequency of the light emitted when an electron in a hydrogen atom makes each transition: a. n = 4 - n = 3 b. n = 5 - n = 1 c. n = 5 - n = 4 d. n = 6 - n = 5

An argon ion laser puts out 5.0 W of continuous power at a wavelength of 532 nm. The diameter of the laser beam is 5.5 mm. If the laser is pointed toward a pinhole with a diameter of 1.2 mm, how many photons will travel through the pinhole per second? Assume that the light intensity is equally distributed throughout the entire cross-sectional area of the beam. (1 W = 1 J>s) Hint: Use the formula for the area of a circle (A = pr2) to find the cross-sectional area of the beam and of the pinhole and determine what fraction of the power gets through the pinhole.

In a technique used for surface analysis called auger electron spectroscopy (AES), electrons are accelerated toward a metal surface. These electrons cause the emissions of secondary electrons called auger electrons from the metal surface. The kinetic energy of the auger electrons depends on the composition of the surface. The presence of oxygen atoms on the surface results in auger electrons with a kinetic energy of approximately 506 eV. What is the de Broglie wavelength of one of these electrons?

Suppose that in an alternate universe, the possible values of l are the integer values from 0 to n (instead of 0 to n - 1). Assuming no other differences between this imaginary universe and ours, how many orbitals would exist in each level? a. n = 1 b. n = 2 c. n = 3

Suppose that, in an alternate universe, the possible values of ml are the integer values including 0 ranging from -l -1 to l +1 (instead of simply -l to +l). How many orbitals exist in each sublevel? a. s sublevel b. p sublevel c. d sublevel

The speed of sound in air is 344 m>s at room temperature. The lowest frequency of a large organ pipe is 30 s-1 and the highest frequency of a piccolo is 1.5 * 104 s-1. Determine the difference in wavelength between these two sounds.

A laser produces 20.0 mW of red light. In 1.00 hr, the laser emits 2.29 * 1020 photons. What is the wavelength of the laser?

A particular laser consumes 150.0 watts of electrical power and produces a stream of 1.33 * 1019 1064-nm photons per second. What is the percent efficiency of the laser in converting electrical power to light?

The wave functions for the 1s and 2s orbitals are as follows: 1s c = (1>p)1>2 (1/a3>2 0 ) exp (-r>a0), 2s c = (1>32p)1>2 (1/a3>2 0 ) (2-r>a0) exp(-r>a0) where a0 is a constant (a0 = 53 pm) and r is the distance from the nucleus. Use a spreadsheet to make a plot of each of these wave functions for values of r ranging from 0 pm to 200 pm. Describe the differences in the plots and identify the node in the 2s wave function.

Find the velocity of an electron emitted by a metal whose threshold frequency is 2.25 * 1014 s-1 when it is exposed to visible light of wavelength 5.00 * 10-7 m.