Science of chemistry links

Anybody that is learning chemistry needs to refer to periodic table of elements. Although, inorganic or general chemistry uses the most, organic chemistry requires the knowledge of periodic trends and periodicity to well understand organic chemistry reaction. Here is one of the link Jenni has come across "periodic table" that explains everything you need to know about the elements. Also, people taking introductory organic chemistry should find good help from the orgachemistryhelp site as well. Please, feel free to share or comment any of these topics.