Element Nomenclature: What Do We Call an Element?
Imagine you discover a new island. You can't just call it "that place" — you need a name, a symbol on a map, and a way to write it in official documents. The same happens when scientists discover a new element. Element nomenclature is the system of naming, symbolising, and writing the names of chemical elements.
The Intuition: Why Bother with Rules?
Before the modern system, elements had chaotic names. Hydrogen was called "inflammable air," oxygen was "dephlogisticated air." Imagine memorising 118 such names. Worse, different countries used different names for the same element — iron was ferrum in Latin, loh in Hindi, Eisen in German. Scientists couldn't communicate clearly.
So the International Union of Pure and Applied Chemistry (IUPAC) stepped in. They created a universal system so that a chemist in Tokyo, a student in Mumbai, and a researcher in Paris all mean the same thing when they write "Fe" or "sodium."
The Precise Statement
Element nomenclature has three layers:
- The name — a unique, official English name (e.g., sodium, gold, carbon)
- The symbol — a one- or two-letter abbreviation (e.g., Na, Au, C)
- The systematic name — a temporary, descriptive name for newly discovered elements before they get a permanent name
Permanent name: chosen by discoverers, approved by IUPAC
Symbol: first letter capital, second letter lowercase (never "NA" or "na")
Systematic name: based on atomic number (e.g., element 118 = ununoctium, symbol Uuo)
The Rules in Detail
1. Permanent Names and Symbols
- First letter always capital, second letter always lowercase: Co (cobalt), not CO; Na (sodium), not NA.
- Symbols often come from Latin names: Ferrum → Fe (iron), Aurum → Au (gold), Stannum → Sn (tin).
- Some symbols come from German: Wolfram → W (tungsten).
- Newer elements are named after people, places, or properties: Curium (Cm) after Marie Curie, Californium (Cf) after California, Technetium (Tc) from Greek technetos (artificial).
Never write "CO" for cobalt — that's carbon monoxide. Never write "NA" for sodium — that's not a valid symbol. The case matters.
2. Systematic Names for New Elements
When a new element is discovered (say, element 117), it gets a temporary name until IUPAC approves a permanent one. The systematic name is built from the atomic number using these roots:
| Digit | Root |
|---|
| 0 | nil |
| 1 | un |
| 2 | bi |
| 3 | tri |
| 4 | quad |
| 5 | pent |
| 6 | hex |
| 7 | sept |
| 8 | oct |
| 9 | enn |
The name is formed by stringing the roots together, then adding -ium. For element 117: 1-1-7 = un-un-sept-ium = ununseptium (symbol Uus). When it got its permanent name, it became tennessine (Ts).
| Atomic number | Systematic name | Symbol | Permanent name |
|:---:|:---:|:---:|:---:|
| 113 | ununtrium | Uut | nihonium (Nh) |
| 115 | ununpentium | Uup | moscovium (Mc) |
| 117 | ununseptium | Uus | tennessine (Ts) |
| 118 | ununoctium | Uuo | oganesson (Og) |
3. Spelling and Pronunciation
- Names are not capitalised in English (except at the start of a sentence): "sodium chloride," not "Sodium chloride."
- British vs. American spelling: aluminium (UK) vs. aluminum (US) — both accepted, but IUPAC uses aluminium. …