Which gas is an example of a monoatomic molecule?

A monoatomic molecule is a molecule that consists of only a single atom. Many noble gases in the periodic table exist naturally as monoatomic molecules because they are chemically stable and do not easily form bonds with other atoms. Examples of monoatomic gases include Neon (Ne) and Argon (Ar).

In contrast, gases like Nitrogen (N₂), Hydrogen (H₂), and Oxygen (O₂) exist as diatomic molecules under normal conditions, meaning they naturally pair up as two atoms. For instance, N₂ has two nitrogen atoms bonded together, H₂ has two hydrogen atoms, and O₂ has two oxygen atoms. These diatomic molecules are stable due to the sharing of electrons in a covalent bond.

Monoatomic gases, such as Neon and Argon, belong to the noble gas group in the periodic table. They are found in Group 18, which contains helium, neon, argon, krypton, xenon, and radon. These gases have complete valence electron shells, making them chemically inert and unlikely to react under standard conditions. This is why they exist naturally as single atoms, rather than forming molecules.

Understanding monoatomic and diatomic gases is important in Chemistry because it explains atomic stability, molecular bonding, and the behavior of gases in different reactions. Monoatomic gases are often used in lighting (like neon lights), welding (argon gas), and other industrial applications due to their non-reactive nature.

In summary, Neon and Argon are examples of monoatomic molecules. They consist of single atoms, are chemically inert, and differ from diatomic gases such as nitrogen, hydrogen, and oxygen, which naturally exist as two-atom molecules. This distinction is key for understanding molecular chemistry and the properties of gases.