QPeriodic is a modification of the Multilingual Periodic Table, originally made by Nick Steen and later modified by Adriweb & Excale, adding the information translations and optimizing the script. QPeriodic builds on these modifications, adding the ability to navigate the periodic table by entering the first letter or the Z number of the required element. When a query is entered, matching elements are highlighted, and, if the query is precise, pressing Enter opens the element's info page.
You can download both the TNS document and the Lua source code here. I only tested it on an Nspire CX with OS 3.2, but it should work on other Nspires (including non-CX ones) with OS >= 3.0.
I hope you will find this script useful.