UPPSC PCS 2025 · Question 148 of 150
Science
Statement 1 is correct: Isotopes are atoms of the same element that have the same number of protons (same atomic number) but different numbers of neutrons, resulting in different mass numbers. Example: Hydrogen has three isotopes — Protium (¹H), Deuterium (²H), and Tritium (³H).
Source: selfstudywala.com UPPCS Prelims 2025 GS Paper 1 detailed solution (based on UPPCS official answer key)
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