- If a target nucleus in Rutherford’s scattering experiment were suddenly to double its number of neutrons, how would the force felt by each alpha particle change?
- If a target nucleus in Rutherford’s scattering experiment were suddenly to double its number of protons, how would the force felt by each alpha particle change?
- How many electrons does it take to create a charge of −1 μC?
- How many protons does it take to make a charge of 1 pC?
 Calculate the ratio of the mass of the proton to that of the electron.
- How many electron volts are there in one joule of energy?
- Consider an electron in each of two energy levels at −2 eV and −1 eV. Which electron can be ionized by lower frequency light?
- In the hydrogen atom, which transition emits a higher frequency photon of light, n = 3 to 2 or n = 4 to 2?
 The ground state of the hydrogen atom is at −13.6 eV. What wavelength of light (in nanometers) is required to ionize a hydrogen atom, i.e., remove the electron from the ground state to n = ∞?
- Consider three different energy levels of a particular atom: E1 = −10 eV, E2 = −3 eV, and E3 = −1 eV. List all the different possible energies for electron transitions among these three energy levels. What other energy level transitions are there if you also include transitions with the E∞ = 0 (ionization) level?
- Niels Bohr’s model of the atom described it as having fixed “positions” (represented by a combination of numbers and letters) that could only hold one electron each. What are these “positions” called?
- quantum states
- quantum orbitals
- quantum ions
- quantum equations
- A hydrogen atom with its electron in the ground state of −13.6 eV absorbs a photon with an energy of 15.0 eV that ionizes the atom. What is the kinetic energy of the electron ejected from the atom?
| | - The n = 2 state of the hydrogen atom is at −3.4 eV. What wavelength of light (in nanometers) is required in to ionize a hydrogen atom with its electron in the n = 2 energy level?
 In the Bohr model of the hydrogen atom, the energy levels are given as
- Calculate the energy levels in electron volts for n = 1, 2, 3, 4, and 5.
- Calculate the energy lost (in electron volts) by the electron that makes a transition from n = 2 to 1.
- What is the frequency of the photon (in hertz) that would be emitted if the electron changes its energy level from n = 2 to 1?
- What is the frequency of the photon (in hertz) that would be emitted if the electron changes its energy level from n = 3 to 2?
- A photon with a wavelength of 434 nm is absorbed by the atom. What is the energy of the photon (in electron volts)? What energy level transition was caused by absorbing this photon?
- Green light has a wavelength of λ = 500 nm (5.0×10−7 m) in a vacuum.
- What is the energy of one photon of green light? Express this both in joules and electron volts. (1 eV = 1.6×10−19 J.)
- What is the momentum (in kilogram-meters per second or newton-seconds) of an electron that has the same wavelength as a photon of green light?
- Divide your answer to Part b by the mass of an electron (me = 9.11×10−31 kg). What does this ratio correspond to?
- Compare your answer in Part c to the speed of light in a vacuum (c = 3.0×108 m/s).
- A photon of red light has a wavelength of 700 nm in a vacuum (λ = 5.0×10−7 m). Use this as a starting point to investigate the consequences of the uncertainty principle:
- Calculate the energy in joules of one photon of red light.
- Suppose that you have an electron whose kinetic energy equals the value you computed in Part a. Now imagine that you wish to measure the electron’s energy with 10% precision. According to the uncertainty principle, for how long (in seconds) must you observe the electron?
- Compare the measurement time interval you calculated in Part b with the period of a photon of green light.
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