Program: Periodic Version: Who knows? System: TI83 BASIC Author: Esben T Date: 11.08.98 Periodic is - as you might have guessed - a periodic system. I know there are other periodic-programs out there (both in asm and BASIC), but they are (at least the ones I've seen:-) very big and very slow (except the asm versions). Periodic (this version:-), is neither big or slow, where the other BASIC versions take up around 2500 bytes (one asm I saw uses even more than 6000 bytes, it had some advantages though), Periodic only uses 501 bytes (plus 984 + 940 for the lists PERI and ENEGA, which are needed). How to use: Periodic can handle both atomic numbers (this I have not seen in other BASIC versions:-) and symbols, though only to element no. 103 or Lr. (The list PERI contains 1-107, but that's because I use it with my program ATOMMASS too:-) As something new I added electronegativity on the output screen (I think Periodic once again is the only one to have this feature:-) ex. 1 ex. 2 ?Pu ?2 (new screen) (new screen) Symbol: Pu Symbol: He Atomno: 94 Atomno: 2 Mass: 244 Mass: 4.0026 E-neg: 1.3 E-neg: 0 Periodic destroys Str1, Str2, X, Y and M (in ex. 1 also P and U are created if they did not already exist. As far as I know P and U will not be destroyed, when already existing, but you might not experience the same:-). The mass is stored in M for use in other physics or chemistry progs. The e-neg-value is not stored. Feel free to distribute Periodic, just make sure this file goes with it. If you feel something is missing in the prog or could be done in a better way, just go ahead and make the changes you need, but please remember to credit me. By the way, the program is protected, so to edit you will need Zprot/Zunprot by Bob Ziuchkovski or TI's win-based editor Esben T email: e_torbensen@hotmail.com