Periodic Table 5 is a Mac program that comes as an alternative to studying chemical elements from the paper version of the Mendeleev table. Besides showing you the well-known chemical chart, this application also provides you with a lot of information regarding all elements from the table, like their name etymology, atomic weight, boiling point, etc.
The utility lets you select the element you wish to study from the table or use the built-in search tool to locate it. Afterwards, it gives you access to dozens of details regarding the chemical element. An important advantage is that you can change the measuring units if you like to (for instance, a boiling point - from Fahrenheit to Celsius).
This program also provides you with options to customize the appearance of the periodic table, toggle windowed or full screen mode, and lets you export custom tables as PNG files.
Periodic Table 5 also comes with a comprehensive help guide which might come in handy to average computer users.
To sum things up, I think it's worth buying this program if you're a chemist or chemistry student. The application provides you with plenty of useful features, comes with a straightforward interface, and is affordable.