The element that has the atomic number 1 is Hydrogen. It is the first element on the periodic table and is the lightest of all elements.
Hydrogen is a colorless, odorless gas at room temperature and is highly flammable. It consists of one proton and one electron, making it the simplest and most abundant element in the universe, forming about 75% of its elemental mass.
Hydrogen plays a vital role in the chemical reactions that take place in stars, including our Sun, where it is fused into helium under extreme pressure and temperature. This process releases a significant amount of energy, which is why stars shine.