The element with atomic number 1 is hydrogen. As the first element on the periodic table, hydrogen is the simplest and lightest, consisting of just one proton and one electron. It is a colorless, odorless gas at room temperature and is crucial to various organic compounds. In the universe, hydrogen is the most abundant element and plays a key role in the formation of stars and galaxies. Its energy production capabilities make hydrogen an important resource in clean energy technologies, such as fuel cells, which convert hydrogen and oxygen into electricity and water, offering a sustainable alternative to fossil fuels.