Atoms, Molecules and Nuclei

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<ol><li> 1. ATOMS, MOLECULES AND NUCLEI 1. What is the minimum angular momentum of the electron in an hydrogen atom? Ans: h/2. 2. Which physical quantity of an atomic electron has the dimensions same as that of h? Ans: Angular momentum. 3. How do the potential and kinetic energies of the electron in a hydrogen atom change when the atom is raised from the ground sate to an excited state? Ans: For the electron in a hydrogen atom, potential energy = - 4 2 2 2 0 me 4 h n and kinetic energy = 4 2 2 2 0 me 8 h n </li><li> 2. Thus, when the atom is raised to one of its excited sates (higher n), the electrons potential energy increases (becomes less negative) and kinetic energy decreases. 4. How many spectral series are possible in the hydrogen spectrum? Ans: Infinite. The last(sixth) of the named series in the hydrogen spectrum is the Humphreys series which results from transitions to nf = 6 from ni = 7, 8, 9, .... etc. in the far infrared region. Further series are unnamed but follow the same pattern. Their lines are increasingly faint showing that they correspond to increasingly rare atomic events. [Note: There are infinite numbers of lines in each series. The spacing between adjacent lines decreases with decreasing wavelength, converging to the so- called series limit or short wavelength limit. </li><li> 3. 5. Which hydrogen spectral series was found first? Ans: The Balmer series in the visible region. Keep on visiting for more study material about MH-CET / JEE Main. - Team Ednexa </li></ol>


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