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==Isotopes==

==Isotopes==

The most common form of hydrogen is protium, although this name is rarely used and it is generally known simply as hydrogen.  Protium [[atom]]s normally consist of a single [[proton]] orbited by a single [[electron]]. Two other [[isotopes]] are known to exist: [[deuterium]], which has one neutron and an atomic weight of 2, and [[tritium]] with two neutrons and an atomic weight of 3. [[Tritium]] is [[radioactive]], with a [[half-life]] of 12.32 years. Naturally occurring tritium is extremely rare on Earth but has a number of valuable applications, such as light-emitting inserts for optical instruments and emergency equipment. As a result it is extremely expensive.  

The most common form of hydrogen is protium, although this name is rarely used and it is generally known simply as hydrogen.  Protium [[atom]]s consist of a single [[proton]] orbited by a single [[electron]]. Two other hydrogen [[isotopes]] are known to exist: [[deuterium]], which has one neutron and an atomic weight of 2, and [[tritium]] with two neutrons and an atomic weight of 3. [[Tritium]] is [[radioactive]], with a [[half-life]] of 12.32 years. Naturally occurring tritium is extremely rare on Earth but has a number of valuable applications, such as light-emitting inserts for optical instruments and emergency equipment. As a result it is extremely expensive.  

==Compounds==

==Compounds==