UPSC Combined Geo-Scientist
Chemist
- 3 descriptive papers
- 200 marks each
- 3 h per paper
Mains Paper I covers inorganic chemistry.
Chemistry of d- and f-block elements: every question, 2016 to 2025
35 parts worth 290 marks have been set on this unit in UPSC Geo-Scientist Chemistry Mains Paper I from 2016 to 2025. Each one opens on its own page with the question, the answer in brief and the key points.
d-block elements: general comparison of 3d, 4d and 5d elements in terms of electronic configuration, elemental forms, metallic nature, atomization energy, oxidation states, redox properties, coordination chemistry, spectral and magnetic properties. f-block elements: electronic configuration, ionization enthalpies, oxidation states, variation in atomic and ionic (3+) radii, magnetic and spectral properties of lanthanides, separation of lanthanides (by ion-exchange method).
Notes: Lanthanides and actinides: contraction, magnetism, spectra, separation (full notes) · short notes
Notes: Transition elements: 3d, 4d and 5d compared (radii, oxidation states, redox) (full notes) · short notes
Notes: Periodic properties: Slater's rules, radii, ionisation and electron-gain enthalpy, electronegativity (full notes) · short notes
2025
- Q1(h) Tendency to form metal clusters5 marks Answered
- Q1(j) First ionisation enthalpy of 5d elements5 marks Answered
- Q8(b) Consequences of the lanthanide contraction15 marks Question only
- Q10(c) Electronic configuration and magnetic moment of La³⁺, Gd³⁺, Lu³⁺10 marks Answered
2024
- Q1(j) Why ordinary lanthanoid carbonyls are unstable5 marks Answered
- Q6(c)(i) Lanthanoid–EDTA formation enthalpy5 marks Answered
- Q6(c)(ii) Non-stoichiometry of f-block oxides5 marks Answered
- Q11(b) High oxidation states in the first d series10 marks Answered
- Q11(c)(i) Why HfO₂ is denser than ZrO₂5 marks Answered
- Q11(c)(ii) Coordination numbers of first-row metals5 marks Answered
2023
- Q10(a) Atomic radii across the 3d series10 marks Answered
- Q10(b) Lanthanoid contraction and hydroxide basicity10 marks Answered
- Q10(c) Ion-exchange separation of lanthanoids10 marks Answered
2022
- Q1(j) Oxidising power across the series5 marks Answered
- Q11(a) Why 4d and 5d radii are similar10 marks Answered
- Q11(c) Ion-exchange separation of lanthanoids10 marks Answered
2021
- Q3(b) d-block diversity and lanthanoid similarity10 marks Question only
- Q3(c) Sharp lanthanoid spectra15 marks Question only
2020
- Q1(j) Transition elements and CuCl5 marks Answered
- Q10(b) Praseodymium magnetic moment10 marks Answered
- Q11(a) Variable oxidation states of Cr and Mn10 marks Question only
- Q11(b) Lanthanide ionic radii and ion-exchange separation10 marks Question only
- Q11(c) NiCl₄²⁻, PdCl₄²⁻ and PtCl₄²⁻: structure and magnetism5 marks Question only
- Q11(d) AmO₂⁺ oxidising, Bk³⁺ reducing5 marks Question only
2019
- Q1(e) Oxidation of Fe(II) and Mn(II)5 marks Answered
- Q9(a) Cerium absorption bands5 marks Answered
- Q9(b) Gadolinium moment10 marks Answered
2018
- Q1(j) Anomalous lanthanide radii5 marks Answered
- Q11(a) Ce and Yb magnetic moments15 marks Answered
- Q11(b) Three transition-metal trends15 marks Answered
2017
- Q1(h) Why thorium and uranium are well studied5 marks Answered
- Q1(j) Mo and W radii5 marks Answered
- Q10(c) Weak, sharp absorption bands of lanthanides10 marks Question only
2016
- Q5(b) Magnetism of Gd and Tb10 marks Answered
- Q10(b) Lanthanide configurations and oxidation states10 marks Answered
UPSC Combined Geo-Scientist (Main) Chemistry Paper I: Model Answers 2021 to 2025
- All eleven questions of each paper, with the question printed above its answer
- Titration, gravimetric and nuclear numericals worked with units; structures drawn
- Topic-wise weightage and a topic-wise index