tak se to dělá jinak, aneb tohle měli přímo na webu:
Q: How do I draw an electron pair with ChemSketch?
A:
Draw a structure in Structure mode and switch to Draw mode. On the top toolbar, click Open Template Window. Choose the "Reaction Symbols" template. Click on the electron pair symbol. Your cursor will show the electron dots attached to the pointer. Each time you point at the molecule and click the left mouse button, a pair of electron dots will be drawn. When you are finished drawing electron dots, right click the mouse button.
Draw a structure in Structure mode and switch to Draw mode. From the Template window, open the "Lewis Structures" template, where you can see a table with all possible images of electron pairs.
http://www.acdlabs.com/resources/knowledgebase/faqs/chemsketch_freeware.php
