Which element has the atomic number 8?

The element with atomic number 8 is oxygen. Atomic numbers correspond to the number of protons in an atom's nucleus, and oxygen is the eighth element in the periodic table. Oxygen plays a crucial role in many biological and chemical processes, including cellular respiration, where it is essential for most life forms to generate energy.

In the context of this question, nitrogen, fluorine, and carbon have atomic numbers of 7, 9, and 6, respectively. Understanding atomic numbers is key to recognizing the identity of elements and their positions on the periodic table, which helps in predicting their chemical behavior and reactions. Oxygen's presence is vital not only for respiration but also in the formation of water, as it combines with hydrogen, and it is a part of many organic and inorganic compounds.