Automatic feedback for incorrect answers

Updated 30 Aug 2024

The messages below are automatically generated for incorrect answers submitted by students working on mechanism questions. (The valence error can also apply to skeletal questions.)

When "No credit lost. Try again." appears with the message, students are NOT penalized.
Students lose an answer attempt and any associated credit for wrong answers that ARE penalized. For example, valence errors are penalized.
Use answer evaluators for Marvin JS to compare student answers to the correct or incorrect answer. You can also add additional wrong answer feedback into the evaluators.

Automatic wrong answer feedback	Error code (doesn't appear to students)
Reaction arrows may originate from the midpoint of another arrow, but they must point to a rectangle. Please connect your boxes with reaction or resonance arrows, not with straight lines.	extractArrows
A two-electron electron-flow arrow must not point from one atom to another atom to which it is already bonded. Electron-flow arrows must not connect compounds in different rectangles.	extractFlows
There are no molecules in your response! Error! Empty fragment! At least two atoms within one molecule are not in the same rectangle.	extractMolecules
At least one atom, *C, is inside two rectangles*. The rectangles should not overlap.	failAtomIn2
At least one atom, *C of CH4, is outside any rectangle. All atoms should be within rectangles. The box(es) highlighted in red contain(s) at least one atom with a valence error*. If you don't see any atoms in (those boxes\|that box) underlined in red, try expanding any shortcut groups.	failAtomOutside
At least one stage in your response mechanism is not connected to any other stages with reaction or resonance arrows. There are two or more stages in your response that are connected to three other stages with reaction or resonance arrows. There can be at most one such stage. Every stage of your mechanism must contain at least one compound. A mechanism with a stage that is connected to three others must have a linear part and a cyclic part, and the linear part must start with a stage that is linked to exactly one other. Your mechanism is completely cyclic, and it has no reaction arrows. A mechanism with only one stage that is connected to exactly one other must have a cyclic part. A mechanism with two end stages cannot have a stage that is connected to three other stages. Your mechanism has two first stages. A mechanism can begin only at one place. Your mechanism has electron-flow arrows in both of its two terminal stages, and the arrows connecting them are resonant, so we cannot determine where the mechanism begins or ends. A mechanism cannot have more than one beginning and one end.	findFirstStage
If reaction arrow 1 originates at the midpoint of reaction arrow 2, then reaction arrow 2 must originate at a stage, not at another reaction arrow. If the reaction arrow that points to a box originates at the midpoint of another reaction arrow, then that box should contain only products and no electron-flow arrows. Every reaction arrow must point to exactly one rectangle.	removeBranchedArrows
The highlighted stage has too many reaction or resonance arrows originating from it. The highlighted stage should not have a reaction or resonance arrow pointing to it. The highlighted stage has too many reaction or resonance arrows pointing to it. Your mechanism contains two separate sequences of stages, so it cannot be interpreted. Please connect all your stages into a single sequence.	reorderStages
All resonance arrows must originate from a rectangle and point to a rectangle. All reaction arrows must originate from a rectangle or the midpoint of another reaction arrow and must point to a rectangle. All reaction and resonance arrows must originate from and point to exactly one rectangle. If a reaction arrow originates at the midpoint of another, then the rectangle to which the first reaction arrow points cannot have any other reaction arrows pointing to it or originating from it. A reaction or resonance arrow must not be entirely contained in a single rectangle. It must connect two rectangles or point from the midpoint of a reaction arrow to a rectangle. At least one stage in your response mechanism is connected to other stages with four or more reaction or resonance arrows.	setArrowEndpoints
Each set of reactants or products must be enclosed in a rectangle, and the rectangles must be connected by arrows.	setupMDoc
A mechanism must contain at least two rectangles, one containing starting materials and the other products.	setupStage
At least one of the atoms in your response has an invalid valence. If you don't see an atom highlighted in red, look for an atom that violates the octet rule, or try expanding your shortcut groups.	Valence error. Can also apply to incorrect skeletal answers)