The electron energy in hydrogen atom is given by E n = (–2.18×10-18)/n2 J. Calculate the energy required to remove an electron completely from the n = 2 orbit





Q.19:- The electron energy in hydrogen atom is given by E n = (–2.18×10-18)/n2 J. Calculate the energy required to remove an electron completely from the n = 2 orbit. What is the longest wavelength of light in cm that can be used to cause this transition?

 

Answer:-
ΔE = E E2 = 0 – (–2.18×10-18 J atom-1/22) = 5.45×10-19 J atom-1
ΔE = hν = hc/λ
⇒ λ = hc/ΔE = (6.626×10-34 Js)×(3.0×10ms-1)/5.45×10-19 J = 3.674×10-7 m = 3.674×10-5 cm