EM Radiation & Photoelectric (QT 1–5)
Rank from shortest to longest wavelength: UV, microwave, green light
UV < green light < microwave
Which hydrogen transition has higher energy, n=3→2 or n=4→3?
n=3→2
What are the possible values of ℓ for n=3?
0,1,2
What is the ground-state electron configuration of sulfur (Z=16)?
[Ne] 3s² 3p⁴
Which atom has the larger atomic radius: Na or Cl?
Na
What is the energy in joules of a photon with a wavelength of 600 nm?
3.31×10−19 J
What is the wavelength (in nm) of the Balmer transition n=3→2?
656 nm
Is the quantum number set (n=4, ℓ=2, mℓ=+3, ms=+½) valid?
No
What is the electron configuration of Fe²⁺?
[Ar] 3d⁶
If you double the intensity of light above the threshold frequency, does the number of electrons emitted, their maximum kinetic energy, or both increase?
Only the number of electrons increases; KE_max does not change.
What is one valid set of quantum numbers for the last electron in phosphorus (Z=15)?
n=3, ℓ=1, mℓ=(−1,0,or1), ms=+or-1/2
Which orbital empties first: 4s or 3d
4s
A metal has a work function of 2.3 eV. Will 650 nm light eject electrons from the metal?
No, because 650 nm photons have ~1.91 eV, which is less than 2.3 eV.
A 350 nm photon strikes the same metal (ϕ=2.3 eV). What is the maximum kinetic energy of the ejected electrons in eV, and what is their velocity?
KEmax ≈ 1.24 eV (1.99×10−19 J) & velocity = 6.6×105 m/s