Thorium

noun (mass noun; chemistry)

/ˈθɔːɹiəm/

A weakly radioactive, silvery-white metallic element (atomic number 90) found in monazite sands, which can be converted to fissile uranium-233 in a nuclear reactor and is the basis for Stage 3 of India's three-stage nuclear power programme.

✍️ Usage in a UPSC answer

Given its vast monazite reserves along the coasts of Kerala and Tamil Nadu, India has anchored the third stage of its three-stage nuclear programme on thorium, betting that an indigenous breeder route to clean energy can simultaneously advance energy security and its climate commitments.

Synonyms

actinideradioactive metalfertile fuelnuclear fuelelement Th

🌱 Word Family

thorite (n), thoriated (adj), thorium-232 (n), thoric (adj), thorianite (n)

🔡 Root

Named after Norse god Thor (god of thunder) by Berzelius (1832); -ium = standard chemical element suffix

📜 Etymology

Named in 1832 by Swedish chemist Jons Jakob Berzelius after Thor, the Norse god of thunder; the mineral thorite in which it was first identified was found in Brevig, Norway.

🧠 Memory Hook

THOR-ium: think of the hammer-wielding Norse god Thor powering future reactors — a "thunderous" source of nuclear energy named in his honour.

📝 Seen in UPSC Question Papers

Prelims 2022 — Economic Geography
Prelims 2020 — Nuclear Technology
Prelims 2017 — Nuclear Technology
Prelims 2016 — Nuclear Technology

Real UPSC previous-year questions whose text uses “Thorium” — proof this word earns its place on your list.

🌍 Geography 📖 Seen in: Resources and Environment

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