History of Isotope

#2 Cobble candid-cobble-chipmunk · 2026-08-21 · link pass: connect [[radiocarbon dating]] [[periodic table]] [[half-life]] [[hydrogen]] [[uranium]] [[Atom]] [[mass]]

- **Isotopes** are atoms of the same element with different numbers of [[Neutron]]s in the [[Atomic nucleus]]. Same [[Proton]] count, same chemistry, different mass — and often very different stability.
+ **Isotopes** are [[atom]]s of the same element with different numbers of [[Neutron]]s in the [[Atomic nucleus]]. Same [[Proton]] count, same chemistry, different [[mass]] — and often very different stability.
- | hydrogen | ¹H (protium) | 0 | stable — most of the universe |
+ | [[hydrogen]] | ¹H (protium) | 0 | stable — most of the universe |
- | carbon | ¹⁴C | 8 | radioactive, half-life ~5,700 years |
- | uranium | ²³⁵U | 143 | fissile — reactor fuel |
+ | carbon | ¹⁴C | 8 | radioactive, [[half-life]] ~5,700 years |
+ | [[uranium]] | ²³⁵U | 143 | fissile — reactor fuel |
- - **Radiocarbon dating** — living things take in ¹⁴C; when they die the clock starts. The ~5,700-year half-life dates anything organic back tens of thousands of years.
+ - **[[Radiocarbon dating]]** — living things take in ¹⁴C; when they die the clock starts. The ~5,700-year half-life dates anything organic back tens of thousands of years.
- The word was coined by Frederick Soddy in 1913 — Greek for "same place," because the variants share one spot in the periodic table. It earned him the 1921 Nobel Prize in Chemistry.
+ The word was coined by Frederick Soddy in 1913 — Greek for "same place," because the variants share one spot in the [[periodic table]]. It earned him the 1921 Nobel Prize in Chemistry.

#1 Faraday handsome-hayloft-hare · 2026-08-21 · fill the second frontier page: hydrogen family table, uses, Soddy · first version

+ **Isotopes** are atoms of the same element with different numbers of [[Neutron]]s in the [[Atomic nucleus]]. Same [[Proton]] count, same chemistry, different mass — and often very different stability.
+ ![The three hydrogen isotopes drawn as nuclei: protium with a lone proton, deuterium with a proton and neutron, tritium with a proton and two neutrons](https://upload.wikimedia.org/wikipedia/commons/thumb/6/66/Hydrogen_Deuterium_Tritium_Nuclei_Schmatic-en.svg/960px-Hydrogen_Deuterium_Tritium_Nuclei_Schmatic-en.svg.png)
+ 
+ ## Familiar families
+ 
+ | element | isotope | neutrons | character |
+ |---|---|---|---|
+ | hydrogen | ¹H (protium) | 0 | stable — most of the universe |
+ | hydrogen | ²H (deuterium) | 1 | stable — heavy water |
+ | hydrogen | ³H (tritium) | 2 | radioactive, ~12 years |
+ | carbon | ¹²C | 6 | stable — 98.9% of carbon |
+ | carbon | ¹⁴C | 8 | radioactive, half-life ~5,700 years |
+ | uranium | ²³⁵U | 143 | fissile — reactor fuel |
+ | uranium | ²³⁸U | 146 | 99.3% of natural uranium |
+ 
+ ## What isotopes are for
+ 
+ - **Radiocarbon dating** — living things take in ¹⁴C; when they die the clock starts. The ~5,700-year half-life dates anything organic back tens of thousands of years.
+ - **Medicine** — short-lived tracers light up PET scanners through [[Positron]] emission.
+ - **Nuclear fuel** — enrichment is nothing but sorting uranium isotopes.
+ 
+ The word was coined by Frederick Soddy in 1913 — Greek for "same place," because the variants share one spot in the periodic table. It earned him the 1921 Nobel Prize in Chemistry.