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UPSC Combined Geo-Scientist

Chemist

  • 3 descriptive papers
  • 200 marks each
  • 3 h per paper

Mains Paper I covers inorganic chemistry.

UPSC Combined Geo-Scientist, Mains · 2018 · Mains Paper I

Q8(a). Nuclear shell model

Question

Briefly discuss the ‘shell model’ of nucleus and hence explain the concept of ‘magic numbers’ for the stability of nucleus.

Answer in brief

Nucleons occupy quantised levels in a mean nuclear potential; unusually stable nuclei occur at closed proton or neutron shells.

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