Photons and the Bohr Model

Question 1

Wavelength

Answer 1

Distance between consecutive peaks or troughs in a wave, represented by lambda (in meters)

Question 2

Frequency

Answer 2

(v, represented by Greek letter nu)
Defined as the number of waves per second that passes through a given point in space. Reported typically as 1/sec. or hertz.

Question 3

Hertz

Answer 3

Waves per second. sec^(-1), 1/sec.

Question 4

All electromagnetic radiation travels at?

Answer 4

same speed –> speed of light 3*10^8 m/s.

Question 5

How does frequency and wavelength correlate? How about energy?

Answer 5

Higher frequency means more wavelengths per second. This means higher energy.

Question 6

what is (lamda)(nu)?

Answer 6

m/sec.
describes velocity or speed

Question 7

Planck’s Constant

Answer 7

h = 6.62 * 10^(-34)
proportionality constant between energy carried by a photon and the frequency of an associated wave.

Question 8

Energy formulas

Answer 8

E = h (c / lamda )or E = hv

where E is energy of a photon, h is Planck’s constant, and v is the wavelength (c / lambda)

wavelength = constant / frequency

Question 9

Bohr Model (advantages and limits)

Answer 9

Identifies the energy level or “n” of an electron but limited in describing the actual location of electrons in an atom. This is usually in the atomic orbital.

Question 10

What force of attraction holds the electron in the hydrogen atom?

Answer 10

Columbic attraction

Question 11

Which type of energy needs to be overcome to remove an electron from the atom (potential or kinetic)?

Answer 11

Potential; in other words, Ionization energy

Question 12

What supplies energy to remove the electron from the atom?

Answer 12

Photons

Question 13

If photon has less than the minimum energy needed to eject the electron from the atom, what will happen to the atom?

Answer 13

The electron might go up an energy level.

Question 14

If the photon has exactly the minimum energy needed to eject the electron from the atom, what will happen to the electron?

Answer 14

The electron will separate from the atom

Question 15

If the photon has more than the minimum energy needed to eject the electron from the atom, what will happen to the electron?

Answer 15

The electron will fly off with the kinetic energy

Question 16

Photoelectrons

Answer 16

Electrons that escape the atom after bombardment by a photon. Photons transfer its energy to electrons.

Question 17

Photoelectron spectroscopy (PES)

Answer 17

Allows determination of the ionization energy of all electrons in an atom, where a gaseous sample of atoms is bombarded by X-rays or ultra-violet photons of known energy. The kinetic energies of the photoelectrons ejected are measured.

Question 18

Relationship between the energy of the photon, ionization energy, and the kinetic energy of the photoelectron.

Answer 18

KE_electron = KE_photon - IE