Periodic Table - what standards? So one would think there are fixed criteria for organizing the periodic table. But soon after I made my version available on the web, I discovered that other tables are not so consistent in several areas. In fact, even my reference materials don't agree on those points.

1. What is the official range of the lanthanide and actinide series? In particular, does it include lanthanum/lutetium and actinium/lawrencium? It seems like it does, but some tables put one of the start/end elements in the main table.

2. Which elements are in the other/poor metals?

3. Which elements are in the semi-metal/metalloids?

4. Are there two series with other metals/non-metals, or three with poor metals, semi-metals, and non-metals?

5. Does the halogens have their own series, or are lump together with non-metals?

6. Which series does hydrogen belong to?

7. Is it lanthanide/actine or lanthanoid/actinoid?

No wonder everyone wants to have their own version of the table to match what they believe is the correct classification! I'll update my table once I have these issues sorted out.

Labels: periodic table, reference, science

  ¶ 12:18 AM