Periodic Table Lookup

Features

• Any element: symbol, names in three languages, atomic weight, category, period, group
• Electron configuration (noble-gas shorthand) and electrons per shell
• Four ways to search: number, symbol, name, range (1-20)
• Query a whole group: period 4, transition metals, noble gases, lanthanides, actinides
• All 118 sit in one searchable dropdown grouped by category — search by name in any of the three languages
• Several at once: “Fe Cu Au” returns each of them in order
• Empty input lists all 118, sorted by number, atomic weight or symbol
• Names and categories accepted in Chinese, English and Japanese
• Paste tolerance: full-width digits and Chinese quotation marks are handled

How to use

1. Enter a symbol, a name or an atomic number, or browse the dropdown by category
2. Or enter a group such as “period 4” or “noble gas”
3. The result is split into basics and electrons
4. Leave it empty for the whole table; sort by atomic weight to find the heaviest

FAQ

Why is the atomic weight in brackets?

Brackets (technetium as `[98]`) mean the element has no stable isotope, and the number inside is the mass number of its most stable one. An atomic weight is the weighted average of an element's natural isotopes; technetium, promethium and everything past 84 either does not occur in nature or has isotopes too short-lived for that average to mean anything. So the bracketed value is the standard notation, not a gap in the data.

The Chinese name of element 104 shows as a box. What now?

That is a missing glyph in your font, not a tool error. The Chinese names of elements 104–118 are characters coined in the last decade (𬬻, U+2CB3B, arrived with Unicode 8.0 in 2015) and many system fonts have not caught up. A more complete font usually renders them. Nothing is blocked: the English and Japanese names are shown alongside, and the symbol is universal.

What does the bracket in the electron configuration mean?

It is the noble-gas shorthand: `[Ar] 3d6 4s2` means “copy argon's 18 electrons, then add 3d6 and 4s2”. Iron's first 18 electrons are identical to argon's, so writing them out adds 18 terms and no information. To check it, expand the bracket: `1s2 2s2 2p6 3s2 3p6` is argon. This tool also lists electrons per shell (iron: 2, 8, 14, 2); if the two ever disagree, trust the per-shell counts, which are entered directly.

Why do some elements not follow the filling order?

Because “fill the lowest energy orbital first” is only an approximation (the Aufbau principle). Filled, half-filled and empty subshells are genuinely more stable, so about two dozen elements break the pattern: chromium is `3d5 4s1` rather than `3d4 4s2`, copper is `3d10 4s1` rather than `3d9 4s2`, and palladium is simply `4d10` with no 5s electrons at all. That is real chemistry, not a data error — the tool reports it as it is.

Can I sort by Chinese name or stroke count?

No — the three sort orders are atomic number, atomic weight and symbol. Sorting by Chinese name is of little use anyway: each element has its own dedicated character, so the conventional order is by number; your browser's find function is faster for locating one.