A virtual alternative to molecular model sets: a beginners' guide to constructing and visualizing molecules in open-source molecular graphics software.

OBJECTIVE: The application of molecular graphics software as a simple and free alternative to molecular model sets for introductory-level chemistry learners is presented.

RESULTS: Based on either Avogadro or IQmol, we proposed four sets of tasks for students, building basic molecular geometries, visualizing orbitals and densities, predicting polarity of molecules and matching 3D structures with bond-line structures. These topics are typically covered in general chemistry for first-year undergraduate students. Detailed step-by-step procedures are provided for all tasks for both programs so that instructors and students can adopt one of the two programs in their teaching and learning as an alternative to molecular model sets.