- ISOTOPE
- Element variant
- Carbon-12, e.g.
- Chemistry subject
- Molecular relative
- Atomic relative
- Chemical relative
- Analog of a 43-Across for an entire atom
- Deuterium, vis-à-vis hydrogen
- One of several lead roles?
- Word from the Greek for "same place"
- Heavy hydrogen, e.g.
- Carbon 13 or cobalt 60
- Carbon 12 or cobalt 60
- Chemical cousin
- Uranium 238, e.g.
- Dating material
- One of an element's closely related atoms
- Chemist's study
- The Simpsons minor leaguer
- Deuterium or tritium
- Carbon 13, e.g.
- Elemental variant
- Carbon-14, e.g.
- Tritium, to hydrogen
- I-131, for one
- Literally, "same place"
- Helium-3, e.g.
- Elemental form
- U-238, for one
- Alternative form of an element
- Element having same atomic number as another.
- Element resembling another in atomic number but not weight.
- Element resembling another in atomic structure.
- Form of a chemical element.
- Oak Ridge output.
- Chemical phenomenon.
- One of several elements, having the same atomic number.
- Element much like another.
- Uranium 238, for instance.
- Atomic age word.
- U 235 or U 238, for example.
- Word in atomic terminology.
- Atomist's concern.
- U 235, e.g.
- Nuclide.
- Varied form of element
- Atomic form
- Atomic element
- Ionium, e.g.
- U 235 is one
- Carbon 14, for one
- Cyclotron item
- Element form
- U-235 or C-14, e.g.
- Member of a fictional Springfield baseball team
- Uranium 235, e.g.
- Springfield minor leaguer
- Carbon 14 or uranium 235
- Related element form
- Uranium 235, for one
- Form of an element
- The 2020 discovery mendelevium-244, for one
- Physicist's atom
- Animated Springfield minor leaguer
- Particular form of an element
- Fictional Springfield minor leaguer
- Relative in a science class?
- Deuterium, for one
- Protium, for one
- Deuterium, e.g.
