Periodic Table - Simple (Element name, symbol, atomic number, atomic mass)

Periodic Table - Detailed  (Element name, symbol, atomic number, atomic mass, oxidation state, etc.)

List of Polyatomic Ions

Quantum Mechanics - Energy Level Diagrams, Madelung Rule, and Orbital Diagrams

Periodic Table of Electronegativity Values 

Solubility Rules - for predicting the solubility of an ionic compound in water

Mole Island - graphic organizers, specific to a variety of reactions, to assist with solutions to stoichiometry problems

Vapor Pressure of Water - data for the vapor pressure of water at varying temperatures.

Standard Heat of Formation Values - view a list of ∆H_f° values for many substances.

Bond Enthalpy Values - view a collection of values for bond enthalpies.

Dissociation Constants - K_a and K_b values for several weak acids and weak bases. 

Solubility Product Constants or K_sp Values - K_sp values of a large collection of insoluble salts.