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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

Q11(b). Three transition-metal trends

Question

Explain why (i) Atomic radii of Zr and Hf are virtually identical. (ii) The most common oxidation state of Cu is +2 but that of Ag is +1. (iii) Gold forms Au⁻ ion under suitable conditions but Cu or Ag does not.

Answer in brief

Lanthanide contraction explains Zr/Hf sizes; ionisation and stabilisation energies explain Cu/Ag oxidation states; gold' s unusually high electron affinity favours aurides.

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CoversThree transition-metal trendsPeriodic properties

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