One For Your Science Staff: Periodic Table Explorer
This does more than some other packages I have seen. The download is offered as Zip, Standalone and Executable only. I found that the Zip and Executable only were corrupt after download.
The Standalone is presented as an installer, but once installed seems to be quite portable [I have tested some of the features of the program running from a central location and it all seems to work OK]
Best of all it is freeware. Also the latest release was only a few days ago.
Link: Periodic Table Explorer