The periodic table - classification of elements. Definitions of groups, periods, alkali metals, alkaline earth metals, halogens, and noble gases. How metals, non-metals, and metalloids can be identified by the position on the periodic table. Created by Jay. Introduction to the periodic table. The periodic table - classification of elements. Groups of the periodic table. Counting valence electrons for main group elements.
OPENBook is software developed for blind and visually impaired individuals to read, edit, and manage scanned images from books, magazines, manuals, bills, newspapers, and other printed documents. It essentially turns your computer system into a scanning and reading machine.
open-source Relating to source code that is available to the public without charge. Open-source code is often enhanced, improved, and adapted for specific purposes by interested programmers, with the revised versions of the code are made available to the public. For example, most of the code in the Linux operating system is open-source.