Chem problem!!!!!!!!!!?

Question

An electron in an excited metal atom falls from the 7d orbital to the 6p orbital. If the energy of the 7d orbital is -2.08e-19 J and the energy of the 6p orbital is -6.29e-19 J, what will the wavelength of the emitted photon be in units of nanometers?

Answer 1

Ok so when the atom falls, the energy difference or energy of the electron given off is
4.21x10^-19 Joules

You would first use this equation to find the frequency
E(Energy)= h(Planks constant)*Frequency(v)
E(Energy)/h(Planks constant)=Frequency(v)
therefore
v=4.21x10^-19J/6.626x10^-34 J*sec
v=6.35x10^14sec-1

now use the equation
frequency(v) = c(speed of light)/wavelength(lambda)
frequency(v)* wavelength(lambda)= c(speed of light)
wavelength(lambda)= c(speed of light)/frequency(v)
wavelength=3.00x108m/s*6.35x10^14sec-1
wavelength=4.72x10-7m or 472 nanometers

Answer 2

Subtract to get the change in energy.

E = hv

v = c/L

substitute and get E = h(c/L)

E = change in energy = answer from subraction
h = Planck's constant = 6.63 x 10^-34 J*s
c = speed of light = 3.00 x 10^8 m/s
L = wavelength = unknown

When you solve for wavelength the answer will be in m since all other units cancel. You need to convert to nm knowing that 1 nm = 1 x 10^-9 m

**Please Note**
I am a teacher and I like to lead you to the answer - not work out the problem for you and give you the answer. I feel people learn better by an explanation than they do from being given the answer.