This interactive periodic table allows you to select the elements in your compound, specify the moles of each, and it will calculate molar mass of the compound. Additionally, click on the mass of an element to see the different isotopes of that element. Click the info button to see a photo and physical properties of the element. Drop down menu takes you to a view of common monatomic ions or a list of polyatomic ions. Selecting an element from monatomic ion view will display the neutral elements electron configuration and the number of electrons gained or lost to form the ion.