Diatomic Elements – Definition, Example & More

Diatomic elements are molecules composed of only two atoms, of the same or different chemical elements. The prefix di- is of Greek origin, meaning “two”. If a diatomic molecule consists of two atoms of the same element, such as hydrogen (H2) or oxygen (O2), then it is said to be homonuclear. Otherwise, if a diatomic molecule consists of two different atoms, such as carbon monoxide (CO) or nitric oxide (NO), the molecule is said to be heteronuclear. The bond in a homonuclear diatomic molecule is non-polar.

Diatomic Elements consist of two atoms bonded together. In contrast, monatomic elements consist of single atoms. Many compounds are diatomic, such as HCl, NaCl, and KBr. Diatomic compounds consist of two different elements. There are seven pure elements that form diatomic Elements.


There are major segments that make up the earth’s atmosphere: nitrogen, oxygen, and much a tad sample of argon. To be better precise, nitrogen makes up 78% of the space while oxygen makes up 21%. This oxygen, O2, and nitrogen, N2, have something in common: both are called diatomic elements.

As pure components, diatomic elements are seven particular molecules that are composed of two atoms. All of the elements in this noble group are gases. If we notice at the prefix ‘di-‘ in the word diatomic, it comes from the Greek origin of ‘two.’ One major way to know you are functioning with a diatomic element is to consider its formula. Every molecule has its own unique molecular formula, and for diatomic elements, their formula regularly contains an addendum of 2, which performs two atoms in its arrangement. As an example, the diatomic element oxygen has a formula of O2, meaning there are two separate oxygen atoms present.

Diatomic Elements
Diatomic Elements

At room temperature, there are five diatomic elements, all of which exist in the gas form: hydrogen, nitrogen, oxygen, fluorine, and chlorine. If the temperature is raised slightly higher, two additional elements will be present: bromine and iodine. At room temperature, bromine and iodine commonly exist in the liquid form. However, with that higher temperature, they will also exist as gases.

Diatomic elements are special as the atoms that form it do not like to be alone. That is, you will never find a nitrogen or fluorine atom, for example, hanging out solo. Rather, these atoms will always be paired together because they need to pool resources to have enough electrons. One great way to remember which atoms form the lucky seven diatomic elements is to think of the following mnemonic device: I Bring Cookies For Our New Home. If there is ever a need to identify these diatomic elements on the periodic table, they can be spotted by remembering the ‘seven rule’ as well. Shown in the illustration, if you take your finger and draw the number seven, starting at nitrogen, you will see that six of the diatomic elements are arranged in the shape of a number seven. When drawing the number seven don’t forget about the seventh element, hydrogen.

Remember Diatomic Elements
Remember Diatomic Elements

7 Diatomic Elements

This is a list of the seven diatomic elements. The seven diatomic elements are:

  • Hydrogen (H2)
  • Nitrogen (N2)
  • Oxygen (O2)
  • Fluorine (F2)
  • Chlorine (Cl2)
  • Iodine (I2)
  • Bromine (Br2)

All of these elements are nonmetals since the halogens are a special type of nonmetallic element. Bromine is a liquid at room temperature, while the other elements all gases under ordinary conditions. As the temperature is lowered or pressure is increased, the other elements become diatomic liquids. Astatine (atomic number 85, symbol At) and Tennessee (atomic number 117, symbol Ts) are also in the halogen group and may form diatomic molecules. However, some scientists predict Tennessee may behave more like a noble gas.

While only these seven elements routinely form diatomic molecules, other elements can form them. However, diatomic molecules formed by other elements are not very stable, so their bonds are easily broken.

How To Remember Diatomic Elements

There is an easy way to remember the seven diatomics, the “seven rule.” First, go to element seven (Nitrogen) and then make a seven with your finger through oxygen and fluorine, then down through chlorine, bromine, and iodine. That’s six. The seventh, hydrogen, is the “oddball” of the periodic table, off by itself.

How To Remember Diatomic Elements
How To Remember Diatomic Elements

What Are Diatomic Elements?

At Room Temperature, There Are Five Diatomic Elements, All Of Which Exist In The Gas Form: Hydrogen, Nitrogen, Oxygen, Fluorine, And Chlorine. If The Temperature Is Raised Slightly Higher, Two Additional Elements Will Be Present: Bromine And Iodine.

What Are The 7 Diatomic Elements?

The Seven Diatomic Elements Are:
Hydrogen (H2)
Nitrogen (N2)
Oxygen (O2)
Fluorine (F2)
Chlorine (Cl2)
Iodine (I2)
Bromine (Br2)

Are Diatomic Elements Compounds?

All Compounds Are Molecules, But Not All Molecules Are Compounds (If They Happen To Have Atoms Of The Same Element). Diatomic Molecules Are Molecules Composed Of Only Two Atoms Of Either The Same Or Different Elements. However, Not Every Diatomic Molecule Comprises A Chemical Compound.

How Many Diatomic Elements Are There?

Seven Elements
There Are Seven Elements That Naturally Occur As Homonuclear Diatomic Molecules In Their Gaseous States: Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, And Iodine.

Is Hcl A Diatomic Molecule?

All Other Diatomic Molecules Are Chemical Compounds Of Two Different Elements. Many Elements Can Combine To Form Heteronuclear Diatomic Molecules, Depending On Temperature And Pressure. Some Examples Include Gases Carbon Monoxide (Co), Nitric Oxide (No), And Hydrogen Chloride (HCl).