同位体

• Reading: どういたい
• Romaji: dōitai
• Kanji breakdown: 同 (dō/ona-) — same; 位 (i/kurai) — position, rank; 体 (tai/karada) — body, substance
• Pronunciation: /doː.i.ta.i/

Meaning

Isotope; one of two or more atoms of the same element that have the same number of protons but different numbers of neutrons, resulting in different mass numbers.

A noun used in nuclear chemistry and physics. Isotopes of an element share chemical properties but differ in physical properties and nuclear stability. Radioactive isotopes (放射性同位体) are used in medical imaging, cancer treatment, and carbon dating. Stable isotopes are used as tracers in biochemical research.

Examples

1. 炭素の放射性同位体である炭素14は、考古学的試料の年代測定に広く利用される。 Carbon-14, a radioactive isotope of carbon, is widely used for dating archaeological samples.
2. 水素には軽水素・重水素・三重水素の三つの同位体が存在する。 Hydrogen has three isotopes: protium, deuterium, and tritium.
3. 同位体標識を使った実験により、代謝経路の各ステップを追跡することができた。 Experiments using isotope labeling made it possible to trace each step of the metabolic pathway.

Usage Guide

Context: chemistry, nuclear physics, medicine, archaeology

Tone: neutral

Origin & History

From 同位 (dōi — same position/rank) and 体 (tai — body, substance). 'Same position' refers to occupying the same position in the periodic table — i.e., the same atomic number.

Cultural Context

Era: Modern

Generation: Students and professionals

Social background: Technical