For two isotopes, use the cross method (alligation) to find % abundance quickly.
and scientific notation. A small error in rounding can change your final answer. How PW Helps You Excel
—the reactant that runs out first—is a frequent exam favorite. Laws of Chemical Combination
Some Basic Concepts of Chemistry " is the foundational first chapter of Class 11 Chemistry, and Physics Wallah (PW) provides comprehensive resources for it, including "one-shot" revision videos and detailed modules for JEE/NEET.