Sapling Learning > Flash-based Activity Question Types: 2-D Molecule

Document created by Digital Support on Jan 25, 2017Last modified by Digital Support on Sep 28, 2017
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The 2-D Molecule Module is used to draw static or graded molecules. The molecule editor provides tools for drawing different atoms, bonds, nonbonding electrons, charges, and reaction symbols. Students can be graded according to various tasks, such as selecting an atom and drawing molecules.

To place a two-dimensional molecule in your question, click 2D molecule icon, then click the place where you want your molecule to appear. The following menu will appear.



  1. Delete. Removes this module from the stage.
  2. Revert. Removes changes made to the module in the current tab.
  3. Grading status. Changes the module between static, graded, and interactive.

The tools available to authors and students depend upon the drawing mode and grading options selected. See the Options section below to find out how to switch drawing modes and changing grading options. All of the possible tools are described here.


  1. Atom menu. Select from periodic table plus additional labels to place on the canvas. Click on an existing atom to change the label to the selected atom. Double clicking on an atom in the drawing area and typing the desired element can also change atom labels.
  2. Functional groups menu. This option is only available in organic mode. Select from common functional groups. To add a functional group to a compound, select the desired group, and then click on any atom to convert it to the selected group.
  3. Bond. Click and drag between atoms to add a bond. Or after adding an initial atom, click on the Bond icon and drag to add additional atoms. Click on an existing bond with the Bond tool selected to change between single, double, and triple bonds.
  4. Wedge bonds. This option is only available when chirality is graded. Click and drag between atoms to add a wedge bond.
  5. Charge. Select the Charge tool, then click on an atom. A box will appear in which you can type charges, such as "Mg2+".
  6. Lone electron pair. Select a single or pair of electrons in the Tools bar, then click on an atom. Electrons can be rearranged once placed on an atom by clicking and dragging.
  7. Add/remove hydrogens. This option is only available in organic mode. Use to add or remove hydrogens from a carbon in condensed form. Select either the add hydrogen  or remove hydrogen  icon.
  8. Curved arrow. This option is only available in organic mode. Select Curved arrow and then click and drag from a bond, lone pair, or lone electron to an atom. Click and drag on the arc to reposition the arrow. The arrowhead can be changed between single and double hooks by clicking on the head.
  9. Graded select. This option is only available when grading status is "graded." Select items for grading. When objects are selected in the authoring environment, students must select them in order to be graded correctly.
  10. Select. Use to select objects. Allows for grabbing and moving objects. Multiple objects can be selected and grouped by clicking and holding while moving over the objects.
  11. Reaction symbols. This option is not available to students. Select from a list of standard reaction and equilibrium arrows and plus (+) sign. Both arrows and the plus sign must be placed between two atoms or molecules. Select the symbol and then click on the first atom or molecule; hold and drag to the next atom or molecule to define the connection.
  12. Eraser. Select the eraser and then click on an object to remove it.

The four possible statements under Grading indicate the grading parameters. These options can be changed in the Grading tab. Hovering over the blue ? button highlights which tools students need to use to fulfill the grading parameter.


  1. Hydrogens. This direction to the student indicates whether H atoms on the carbon backbone can be omitted (H atoms on functional groups are still required). When no slash is shown, it indicates that the student must draw all H atoms.
  2. Isometry. This direction indicates to the student that correct isometry must be drawn.
  3. Chirality. This direction indicates to the student that correct chirality must be drawn.
  4. Nonbonding electrons.This direction indicates to the student that nonbonding electrons must be drawn.


Options: Entry Mode

The first setting viewable on the Options tab is Entry Mode. Here you can select between general chemistry or organic chemistry. When the organic chemistry mode is selected, the Add/Remove Hydrogens, Functional Groups, and Curved Arrow buttons are enabled; in organic mode, structures are always shown in line-bond form. In general chemistry mode, the Add/Remove Hydrogens, Functional Groups, and Curved Arrow buttons are disabled, and the Line-Bond option is enabled.


Note: When in organic mode, it is strongly recommended that you uncheck the nonbonding electrons grading option. If you leave this option checked, be sure that the structures drawn in the correct tab show all nonbonding electrons.


Options: Display

Display allows you to specify various options in the appearance of the module.


  1. Hide/Show Grid. Controls the display of the background grid. When this option is checked, the background grid will be shown.
  2. Carbons. Toggles between line-bond and regular structural drawing of carbon bonds.
  3. Snap to Grid. When checked, objects will be aligned to nearest grid lines.


Options: Grading


  1. Student Interactions. These tools control student interactions and the tools shown to a student. These also define the grading criteria. For example, if select only is selected, students cannot be graded on drawing a molecule.
  • Draw and select. Allows students to both draw and select.
  • Draw only. Allows students to place new objects on the canvas.
  • Select only. Allows students to click on molecules or atoms. 


  1. Grading Options. Grading options allow you to select some criteria on which students are graded.
  • Hydrogens. When this option is checked, students must include hydrogens. When it is unchecked, hydrogens will be ignored (unless they are added incorrectly).
  • Isometry. When this option is checked, students will be graded on the isometry defined in the Correct tab. When it is unchecked, isometry will be ignored.
  • Chirality. When this option is checked, students will be graded on the chirality defined in the Correct tab. When it is unchecked, chirality will be ignored.
  • Nonbonding electrons. When this option is checked, students will be graded on entering the nonbonding electrons defined in the Correct tab. When it is unchecked, nonbonding electrons will be ignored.