N-15 is a stable isotope of nitrogen, which is a chemical element represented by the symbol N. It has a mass number of 15, meaning it contains seven protons and eight neutrons in its nucleus. N-15 is commonly used in scientific research, particularly in studies involving plant biology and environmental science, as it helps trace nitrogen cycles and understand nutrient uptake. This isotope is also utilized in nuclear magnetic resonance (NMR) spectroscopy, a technique that provides insights into molecular structures. N-15 can be found naturally in the environment, albeit in small amounts, and is often used in isotopic labeling experiments to track biological processes.