IIT JEE , AIEEE Forum - Chemistry , Physical Chemistry - Structure of atom-conceptual doubt

learner

This is from one of my books, under spectral series ..

Previous paragraphs are about Hatom spectra,ionisation potential and interpreting spectral series..

"If an electron acquires more than enough energy to permit its removal from the atom,extra energy is carried off by it as KE. Because of very small magnitude of the quanta of kinetic energy,this energy is essentially continuously variable. The spectrum beyond the series limit thus appears continuous ; from the position of continuum,we may calculate ionisation potential."

Can someone please explain the underlined part?

Rates assured!

Thanks! :-)

learner

Anyone ????

dev_22oct

well this is a funda of bound and unbound state..

bound state is the state who's energy is less than that of infinite level.....so all the levels below the infinite separation are called bound level....

at times the energy gvn to excite the electron is much more that it take the electron beyond the infinite level so the levels beyond the infinite level is called unbound levels..which results into continium.

infinte level: min dis frm the nucleus where the e does not feel any attraction.

learner

Ok, so that means at n = infinity, the spectrum is no longer line spectrum and becomes continuous?

But what does "continuously variable energy " mean and how is it related to magnitude of KE, as stated in the book?

Thanks!!

cutepooja

i assume u have the basic idea of emission and absorption spectra
since energy of orbit is quantised an electron can take only INCREMENTS of energy corresponding to transition
when photons are absorbed the electrrons move to higher level they remain there fr short time 10*-10
at ordinary temp practically all the h atoms are in lowest state
pls anyone guide me too am i goin correct

cutepooja

photons wid wavelength equivalent to lyman can be absorbed by hydrogen but no intermiddeate wavelength photon can be absorbed as the energies dont allow for transitons
photons less than lyman can be absorbed these photons have enough energy to excite electron to infinity the region of continuous energy level Etotal >o or= o

cutepooja

contd........
when a continous spectrum of radiation is passed thru h most of the wavelengths are not absorbed since their photons dont have the proper energies to excite the atom to an allowed energy state
but wavelengths corresponding to lyman will be absorbed (line absorption)
all wavelengths shorter than lyman will be absorbed as these photons ionise atom & carry the electron to the energy continuim the absorption in this region which u said is continous absorption spectrum

learner

I understood that..thanks!!

But

i still dont see how small KE means continuously variable energy.

Firstly what is continuoulsly variable energy?

Thanks!

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