To embed magnesium-21 with a 2+ charge use:
Which gives:
For sodium which has a symbol of Na use:
https://soriki.com/js/chem/atom-builder/index.html?element=Na
https://soriki.com/js/chem/atom-builder/index.html?element=Na&mass=24
https://soriki.com/js/chem/atom-builder/index.html?element=Na&mass=24&charge=-1
charge
set the charge with charge. Use whole numbers for the charge with the + or -. Even single charges must have an integer value. So, if we need sodium-24 with a -1 charge use:
Based on a work at earthsciweb.org.