1. Colorless: Oxygen gas is colorless. When observing oxygen in its gaseous state, it is virtually indistinguishable from air in terms of color.

2. Odorless and Tasteless: Oxygen is both odorless and tasteless. It does not have any distinguishable scent or taste. This is why we can breathe oxygen without detecting it through our sense of smell.

3. Diatomic Molecule: Oxygen exists as a diatomic molecule, meaning it consists of two oxygen atoms bonded together. The chemical symbol for oxygen gas is O2, indicating the presence of two oxygen atoms.