The chemical element with the symbol 'H' is hydrogen. It is the simplest and most abundant element in the universe, consisting of just one proton and one electron. Hydrogen plays a crucial role in the universe, being a primary fuel for stars through the process of nuclear fusion, where it fuses to form helium and releases a significant amount of energy. Additionally, hydrogen is essential in various chemical reactions and is commonly found in water (H2O) and organic compounds, making it vital for life on Earth.