Which element has the atomic number 1?

The element with atomic number 1 is hydrogen. Atomic number refers to the number of protons found in the nucleus of an atom of an element, and for hydrogen, that number is indeed one. This unique property makes hydrogen the simplest and most abundant element in the universe, often serving as the building block for more complex elements and compounds. Hydrogen is essential in various chemical reactions, particularly in the formation of water and organic molecules.

When considering the other elements listed, oxygen has an atomic number of 8, nitrogen has an atomic number of 7, and carbon has an atomic number of 6. Each of these elements is more complex than hydrogen and consists of a greater number of protons. Thus, hydrogen’s position as the first element on the periodic table reflects its fundamental role in chemistry and the universe.