Question

3. What is the wavelength (in nm) and frequency of light that is emitted when an electron in a hydrogen atom drops from the n = 5 to the n = 3 energy level

Answer 1

Apply Rydberg Formula

E = R*(1/nf^2 – 1/ni ^2)

R = -2.178*10^-18 J

Nf = final stage/level

Ni = initial stage/level

E = Energy per unit (i.e. J/photon)

E = (-2.178*10^-18)*(1/3^2 – 1/5 ^2)

E = -1.548*10^-19

For the wavelength:

WL = h c / E

h = Planck Constant = 6.626*10^-34 J s

c = speed of particle (i.e. light) = 3*10^8 m/s

E = energy per particle J/photon

WL = wavelength in meters

WL = (6.626*10^-34)(3*10^8)/(1.548*10^-19)

WL = 0.0000012841

to nanometers:

WL = (0.0000012841)(10^9) = 1284.1 nm