Periodic Table Explorer is a very complete reference tool. It obviously includes a periodic table of elements and tons and tons of information about each one of the known elements. The main window consists of two panes. The one on the left shows the table of elements, whereas the one on the right displays information about the elements that you select. For example, if you click on Mt (Meitnerium), the right pane will display its full name, group number and name, block, period, state, color, boiling point, melting point, density, discovery information, name origin, sources, uses, history, etc.
At the top of the screen, there is a toolbar with buttons that let you access other modes. There is a mode that shows you pictures of the elements, a search mode, a mode that shows properties of the elements, a mass calculator and, my favorite, a window that shows you a world map and two drop-down menus. There you can look for a country, which will be highlighted in the map. A list of all the elements found in that country will also be shown.
In short, Periodic Table Explorer gives you access to a lot of information in an organized package for only $1.99.