Old...
Well, I understand that this is an app done by an American.
And somehow or another, Americans dont seem to recognize and fix their mistakes.
By that I mean, the elements in Group 12 is no longer considered to be transition metals, but in this app (and all other apps), they still remain to be the transition metals.
Come on, and wake up, Yankees!
Shibumaku about
Mild EleMints: Free Periodic Table