Properties for Marvin JS setup

Select an option to show or hide hydrogen (H) and/or carbon (C) atoms as students draw molecules. By default, Marvin JS adds or subtracts H atoms automatically.

This setting does not impact student grading and is not intended to teach students to add H atoms manually.

• Show H when hetero and terminal, and C when terminal only (Default)
  Turn off this default if you want students to learn by adding H atoms manually.

  

• Show all C and no H
  Applies to the skeletal chemistry drawing answer type, but not to mechanism.

  

• Show all H

  

• Show all H and C

  

• Show hetero H

  

• Show no H
  When Show No H is set and students draw two carbon atoms connected by a bond, they are still graded as if 6 H atoms were also drawn.

  .

To grade H atoms explicitly —
See the Atoms evaluator (expressionOchemEvalAtoms).

To specify the number of H atoms students need to draw —
Select explicit atoms only from the Atoms evaluator (expressionOchemEvalAtoms).

To alert students to any valence errors as they draw, the drawing tool shows valence errors as a red ball.

• Show valence errors —
  This is the default. Valence errors should be shown when the question focus is not on molecular structure, like for a predict-the-product question.

  

• Hide valence errors —
  When students must draw all of their own hydrogen atoms, select Hide valence errors.

The valence error property applies to the skeletal chemistry drawing answer type, but not to mechanism.

Lone pairs are also known as unshared pairs or non-bonding pairs.

• Off by default
• Checking the box shows lone pairs as students draw.

Applies to the skeletal chemistry drawing answer type, but not to mechanism.

Apply this setting to reduce author errors and speed up authoring. This property setting is available for both skeletal and mechanism questions.

• Off by default
• R, S labels are shown when  Calculate stereo (top toolbar) is active and Show R, S labels is selected.

The Three dimensional property provides templates (bottom toolbar) for students to more easily draw chairs and other 3D structures in skeletal drawing questions.

• Off by default
• When selected, 3D buttons appear in the bottom toolbar (instead of the template buttons used for 2D questions) and the  Rotate in 3D button appears in the top toolbar.

Applies to the skeletal chemistry drawing answer type, but not to mechanism.