Why are the noble gases monatomic?

A monatomic element exists as individual atoms rather than being bonded to other atoms, forming molecules. As a result, these elements are typically found as single, uncombined atoms in their natural state.

Noble gases are elements in Group 18 of the periodic table. They have the unique property of having a full valence electron shell, which is the outermost shell of electrons in an atom. The number of electrons in their valence shell is either 2 (for helium) or 8 (for all other noble gases) which makes them have a stable electron configuration. The electron configurations for noble gases can be represented as: 1. Helium (He): 1s^2 2. Neon (Ne): 1s^2 2s^2 2p^6 3. Argon (Ar): 1s^2 2s^2 2p^6 3s^2 3p^6 4. Krypton (Kr): 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^6 5. Xenon (Xe): 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^6 4d^10 5s^2 5p^6 6. Radon (Rn): 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^6 4d^10 4f^14 5s^2 5p^6 5d^10 6s^2 6p^6

Atoms are more stable when their valence electron shell is full. With a full valence shell, atoms are less likely to lose, gain or share electrons with other atoms. This means that they are unlikely to form chemical bonds with other elements, making them chemically stable.

As noble gases have a full valence electron shell, they have a stable electron configuration. This means that they do not readily form chemical bonds with other elements. Due to their chemical stability and lack of reactivity, they exist as single, uncombined atoms. Hence, noble gases are monatomic elements.