Hi, I have the following subjective doubts from atomic structure....
1. What electronic transition in the He^{+} ion would emit the radiation of the same wavelength as that of the first Lyman transition of hydrogen (ie, for an electron jumping from n=2 to n=1)? Neglect the reduced-mass effect. Also calculate the second ionisation potential of He and first Bohr orbit for He^{+}.
2) 13.6 eV is needed for ionisation of a hydrogen atom. An electron in a hydrogen atom in its ground state absorbs 1.5 times as much energy as the minimum energy required for it to escape from the atom. What is the wavelength of the emitted electron?
Any help would be appreciated! :)
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2 Answers
1357First one is easy, think like this
For Hydrogen
1/λ=R[1/12-1/22]
For Helium
1/λ=R*4*[1/n12-1/n22]=R[4/n12-4/n22]
No compare the two
11Q-2 let the minimum energy required to escape the electron be x (as written x=13.6)
so when the electron electron absorbs 1.5x energy , x amount of energy will be absorbed and x/2 will be left . this is the energy of the radiation or the energy of electron emitted ie 13.6/2= 6.8 eV
now energy of radiation = hc/∂ (∂= wavelength of emitted electron)
so,
→ hc∂=6.8
all other are constants calculate ∂ from this