Diatomic
Definition and meaning of Diatomic in chemistry.
The word diatomic describes any chemical molecule that is built from exactly two bonded atoms. These two atoms can be identical to each other, or they can be completely different elements. Recognizing diatomic elements is a very important first step for learning basic chemistry rules.
In more detail
There are exactly seven elements that exist as diatomic molecules in their standard everyday form. These elements are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. They are written with a small number two next to their chemical symbol on paper.
This small fact is extremely important when you are learning how to balance chemical equations. If a word problem mentions oxygen gas, you must write it out as a pair. You cannot use a single atom formula for these seven specific elements in a reaction.
The two atoms are firmly held together by a single, double, or triple covalent bond. The specific type of bond depends entirely on which element or compound you are studying. Nitrogen gas has a very strong triple bond connecting its two atoms tightly together.
This powerful bond is incredibly hard to break apart during a normal chemical reaction. This makes nitrogen gas very stable and mostly unreactive at normal room temperatures. Other diatomic molecules contain two different elements, which makes them heteronuclear chemical compounds.
Key facts
| Field | General Chemistry |
|---|---|
| Common diatomic elements | H2, N2, O2, F2, Cl2, Br2, I2 |
| Bonding type | Covalent (single, double, or triple) |
| Homonuclear example | O2 (two of the same atom) |
| Heteronuclear example | HCl (two different atoms) |
Oxygen gas is a homonuclear diatomic molecule that makes up about twenty percent of our atmosphere. When you breathe in, your lungs are absorbing these paired oxygen atoms to keep you alive. Hydrogen chloride is a heteronuclear diatomic molecule that has one hydrogen and one chlorine atom. When dissolved in water, this simple two-atom molecule becomes a very strong and dangerous acid. This fact shows how two simple atoms can create very powerful chemicals.
Frequently asked questions
What does the prefix "di" mean in diatomic?
The prefix "di" simply means two. A diatomic molecule is a molecule that contains exactly two atoms bonded together, no more and no less.
How do you remember the seven diatomic elements?
Many students use the name "HOBrFINCl" (pronounced Hober-finkle) or the phrase "Have No Fear Of Ice Cold Beer" to remember Hydrogen, Nitrogen, Fluorine, Oxygen, Iodine, Chlorine, and Bromine.
What is the difference between homonuclear and heteronuclear?
Homonuclear means the two atoms are the exact same element, like oxygen gas. Heteronuclear means the molecule is made of two different elements, like carbon monoxide.