Concept Explanation: Atomicity of Noble Gases

Atomicity refers to the number of atoms present in one molecule of an element. Noble gases are elements found in Group 18 of the periodic table, including helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).

Step 1: Understand Noble Gas Properties
Noble gases have a complete outer electron shell, making them highly stable and chemically inert. They do not easily form bonds with other atoms, including themselves.

Step 2: Determine Molecular Structure
Since noble gases do not form molecules with multiple atoms, they exist as individual atoms. For example, helium exists as He, not as He₂ or any larger molecule.

Step 3: Define Atomicity
The atomicity is the number of atoms per molecule. For noble gases, each "molecule" consists of only one atom. Therefore, they are mono-atomic.

Final Answer: The atomicity of noble gases is Mono-atomic.

Related Topics

• Periodic Table Groups
• Chemical Bonding
• Inert Gases
• Molecular Structure

Key Formulae and Theory

Atomicity (A) = Number of atoms in one molecule

For noble gases: $A=1$

Theory: Noble gases have stable electron configurations with full valence shells (octet for most, duet for helium), represented as:

Helium: $1^s{2}^{}$

Others: $n{s}^{2}n{p}^6$ (where n is the period number)