What occurs to the oxygen gas in the atmosphere upon absorbing photons of light?

When oxygen gas in the atmosphere absorbs photons of light, particularly high-energy ultraviolet (UV) radiation, it can undergo a process known as photodissociation. This process involves the breaking of the molecular bonds in diatomic oxygen (O₂), resulting in the formation of individual oxygen atoms (O). This reaction is significant in the upper atmosphere, where high-energy sunlight is prevalent, and is a crucial part of the ozone formation process, as these free oxygen atoms can then react with other oxygen molecules to form ozone (O₃).

The absorption of light energy leads to the splitting of the O₂ molecules into separate atoms, which is an essential mechanism that influences atmospheric chemistry and is central to the formation of the ozone layer that protects life on Earth from harmful UV radiation. Thus, the correct understanding of what happens to oxygen gas when it absorbs light is that it splits into individual oxygen atoms.