The chemical element with the symbol 'Na' is sodium. Sodium is an alkali metal with the atomic number 11 and is highly reactive, particularly in the presence of water. It is a vital element in many biological processes, playing a key role in nerve transmission, muscle contraction, and maintaining fluid balance in living organisms. Sodium is commonly found in nature as part of various compounds, most notably sodium chloride, or table salt. While essential for health in moderate amounts, excessive sodium intake can contribute to high blood pressure and other health issues, highlighting the importance of balance in dietary consumption.