Hydrogen is considered an element. It is the lightest and most abundant element in the universe, consisting of a single proton and typically one electron. In its pure form, hydrogen is a colorless, odorless, and highly flammable gas.
A compound, on the other hand, is a substance composed of two or more different elements chemically combined. While hydrogen itself is an element, it can combine with other elements to form compounds. For example, when hydrogen combines with oxygen, it forms water (H2O), which is a compound.
There are other elements that can exhibit similar behavior, acting as both elements and compounds depending on their chemical bonding. For instance, oxygen (O2) is an element when it exists in its diatomic form, but it can also combine with other elements to form compounds like water (H2O) or carbon dioxide (CO2). Similarly, nitrogen (N2) is an element in its pure form but can combine with other elements to form compounds such as ammonia (NH3) or nitric acid (HNO3). These elements can exist as molecules (diatomic or polyatomic) on their own, but they can also participate in chemical reactions to form compounds with other elements.