Consider the neutral helium atom (He) and the singly-ionised helium ion (He )

CHEMISTRY · Multi-part · CBSE · Chemistry · Structure of Atom · Structure of Atom

Problem

Consider the neutral helium atom (He) and the singly-ionised helium ion (He+^{+}). Both species contain the same nucleus but differ in the number of bound electrons. (i) Give one reason why the Bohr model successfully predicts the spectral lines of He+^{+} but fails for neutral He. (ii) Describe qualitatively how electron–electron interaction alters the potential energy experienced by an electron in a multi-electron atom and thereby invalidates the single-electron orbit picture. (iii) State any two features introduced by the quantum-mechanical model that overcome the difficulty mentioned in part (ii).

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