The symbol for the element hydrogen in the periodic table is "H." Hydrogen is the first element on the periodic table, with an atomic number of 1, indicating it has one proton in its nucleus. As the simplest and most abundant element in the universe, hydrogen is a crucial building block for many compounds, including water (H2O) and organic molecules. It exists as a colorless, odorless gas under standard conditions and plays a vital role in various chemical reactions, particularly in the processes of combustion and respiration. Hydrogen's unique properties have made it an area of interest in energy research, especially in fuel cells.