Which of the following diatomic elements is represented by H2?

H2 represents molecular hydrogen, which is a diatomic element composed of two hydrogen atoms bonded together. Hydrogen is the simplest and lightest element on the periodic table, characterized by having an atomic number of 1. It naturally exists as a diatomic molecule in its most stable form, which is represented as H2.

In contrast, the other options refer to different diatomic elements: oxygen exists as O2, nitrogen as N2, and fluorine as F2. Each of these elements also forms diatomic molecules under normal conditions, but they are distinctly different from hydrogen. Understanding the diatomic nature of these elements is important, as many elements in their gaseous forms tend to pair up to achieve stability. Hydrogen's unique position as the lightest and most abundant element on the universe is what makes it particularly significant in various chemical and physical processes.