Atomic Models

Problems

practice

1. An excited electron in a hydrogen atom falls from the n = 6 energy level to the n = 4 energy level. Determine the following quantities for the emitted photon:
   1. its energy in electronvolts
   2. its energy in joules
   3. its frequency
   4. its wavelength
   5. its momentum
   6. its band in the electromagnetic spectrum
2. Write something.
3. Write something.
4. Write something completely different.

numerical

1. A photon with a frequency of 5.02 × 10¹⁴ Hz is absorbed by an excited hydrogen atom. This causes the electron to be ejected from the atom, forming an ion.
   1. Calculate the energy of the photon in joules.
   2. Determine the energy of the photon in electronvolts.
   3. What is the number of the lowest energy level (closest to the ground state) of a hydrogen atom that contains an electron that would be ejected by the absorption of this photon?
   4. What is the kinetic energy of the ejected electron in electronvolts?
   5. What is the kinetic energy of the ejected electron in joules?
   6. How fast is the electron moving?
2. Cesium is the element with the lowest ionization energy (3.8939 eV). Helium is the element with the highest (24.5874 eV).
   1. What are the wavelengths of the photons with the minimum energy needed to ionize cesium and helium, respectively?
   2. What kind of electromagnetic radiation is each photon? Compile your results in a table like the one below.
   3. What general rule of thumb for health and safety do these calculations show?

   Elements with extreme ionization energies

   	cesium (lowest)	helium (highest)
   ionization energy	3.8939 eV	24.5874 eV
   wavelength of photons capable of ionizing this element
   type of electromagnetic radiation