1. Diatomic Hydrogen (H₂):
* This is the pure elemental form of hydrogen, found as a colorless, odorless gas.
* It's a major component of the atmospheres of the gas giant planets like Jupiter and Saturn.
* It's also found in small quantities in Earth's atmosphere.
2. Water (H₂O):
* The most common compound containing hydrogen on Earth.
* It's a vital component of all life, covering about 71% of Earth's surface.
3. Organic Compounds (e.g., hydrocarbons, carbohydrates, proteins, fats):
* Hydrogen is a key component of all organic molecules.
* These compounds form the basis of life and are found in all living things.
* Examples include methane (CH₄), glucose (C₆H₁₂O₆), and DNA.
4. Acids:
* Many acids contain hydrogen.
* Examples include hydrochloric acid (HCl), sulfuric acid (H₂SO₄), and nitric acid (HNO₃).
5. Other Compounds:
* Hydrogen is found in a wide range of other compounds, including:
* Ammonia (NH₃)
* Hydrogen sulfide (H₂S)
* Sodium hydroxide (NaOH)
* Many metal hydrides (e.g., lithium hydride (LiH), sodium hydride (NaH))
Important Note: While hydrogen can be found in many forms and compounds, it's rarely found in its elemental form (H₂) on Earth. This is because hydrogen is very reactive and readily bonds with other elements to form compounds.
