Valence & Formula Practice2026

Valence & Formula Practice is an offline study tool for junior chemistry learners, useful for previewing lessons, correcting homework, and preparing for exams. The app focuses on the common challenge of writing chemical formulas. It provides quick lookup for common element valences, polyatomic ion cards, crisscross method practice, true or false checks, and mistake review. All content stays on the device. No login, no internet connection, and no personal data collection are required. Key features: 1. Quick lookup for common element and ion group valences by name, symbol, and category. 2. Chemical formula writing practice covering oxides, acids, bases, salts, and other common question types. 3. Crisscross method step hints to explain subscript reduction and positive-negative valence balancing. 4. Mistake notebook and mastery statistics that track weak elements and error-prone topics. 5. Offline question bank and focused practice templates for daily drills and exam review.