About this app
With the Building Atoms, Ions, and Isotopes app, explore the composition of the elements. Build atoms, ions, and isotopes by selecting appropriate numbers of protons, neutrons, and electrons. For reference, this app also includes atomic theory information and a periodic table that is interactive in the iPad version.
Latest release
What’s New
bug fixes
Audience growth
Ratings growth
Baseline captured. Growth appears after the crawler observes a changed rating count.
Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.
Price tracking
Price intelligence
First snapshot captured. The trend line starts after the next crawler price observation.
- First observed Aug 20, 2026 · 2:36 AM $1.99
Screenshots
