Weakest practiced elements
Mastery is local evidence only: accuracy × amount practiced. It is not a chemistry grade.
PERIODIC TABLE · REFERENCE + MASTERY EXPLORER
Periodic Table
Explore all 118 elements, see the pattern, then prove you can recall it.
Search, filter, color by properties, switch between table and list, inspect electron structure, compare elements, export a local reference, or jump into Daily, typed quiz and blank-table recall. Local mastery keeps weak elements visible without an account.
ModeExplore
QUIZH
Type the element name.
symbolOPEN RECALL
Type names or symbols to fill the real table
Produce elements in any order. Only recalled or revealed tiles are filled.
Explore the table or choose a recall mode.
Family colors are structural labels118 elementsArrow keys move selection · / search · D daily · Q quiz · R recall · F focus
Two-element structural compare
Local sessions
Last 30 days
Daily 12 is deterministic by date and rotates Foundations, Core and Full scopes while keeping Today’s 6 unchanged.
Explore
Search by name, symbol or atomic number, then filter the real table by family, block or room-temperature state.
Quiz 10
Typed name/symbol/number questions mix with exact position, family and block recall.
60s Recall
Type as many element names or symbols as you can. Correct recalls fill their real positions.
Weak Review
Missed elements rise into a local review queue; strong items fade out naturally as evidence improves.
Reference scope: V0.409 expands the single-page explorer with a frozen offline property layer for study: atomic mass, covalent and van der Waals radii, outer electrons, common isotope, electron configuration/shells, family, block and room-state classification. It does not claim the isotope-decay, compound, thermodynamic or media breadth of specialist chemistry databases. For laboratory or citation-critical work, verify against current IUPAC/NIST/PubChem sources.