Calculate the energy, in joules, required to ionize a hydrogen atom when its electron is initially in the n = 4 energy level. Before doing the calculation, predict whether this energy is greater than or less than the +2.18 times 10^-18 J needed to ionize a ground-state hydrogen atom. The transition with the longer wavelength is The energy is less than +2.18 times 10^-18 J The energy is greater than +2.18 times 10^-18 J The energy for ionization from the n = 4 state is
where B = 2.18 x 10-18 J and Z = charge onnucleus (number of protons).
2. Anelectron in the 4th energy level of the H atom drops tothe 1st energy level. In other words an excited electrondrops to the ground state. What is the energy (in J) of the emittedphoton)? The energy of an electron in the nth level is
En =
-
Bn2
=
-
2.18 x 10-18 Jn2
3.The photoelectric effect for a certain alloy has a thresholdfrequency of 8.40 x 1014 Hz. For light of thisfrequency, find the energy of one mole of photons (inkJ).