M

Molecule

Smallest particle of an element/compound; N_A = 6.022×10²³ molecules/mol
Quick Reference
Formula / NotationSmallest particle of an element/compound; N_A = 6.022×10²³ molecules/mol
Also Known AsMolecular unit, chemical molecule, covalent molecule, polyatomic molecule

What is Molecule?

The smallest unit of a covalent compound that retains its chemical identity. Molecules consist of two or more atoms held together by covalent bonds. Diatomic molecules (H₂, O₂, N₂) contain two atoms; polyatomic molecules contain more than two atoms.

Formula & Notation

Smallest particle of an element/compound; N_A = 6.022×10²³ molecules/mol

Other Names / Synonyms: Molecular unit, chemical molecule, covalent molecule, polyatomic molecule

Properties & Characteristics

A molecule is the smallest particle of a substance that has the chemical properties of that substance and exists independently. Molecules consist of two or more atoms held together by covalent bonds. Diatomic molecules (H₂, N₂, O₂, Cl₂) consist of two atoms. Polyatomic molecules (H₂O, NH₃, C₆H₁₂O₆) have three or more atoms. Noble gases are monatomic molecules. Molecular mass = sum of atomic masses. Molecular properties (shape, polarity, reactivity) determine physical properties.

Uses & Applications

The molecule concept is the basis of all molecular chemistry: drug-receptor interactions require the correct molecular structure; polymer chains are linked molecules; biochemical processes involve molecular recognition; analytical chemistry identifies specific molecules in mixtures.

Safety Information

Individual molecules of toxic substances are responsible for their hazardous effects: a molecule of sarin binds to acetylcholinesterase; a molecule of benzene intercalates into DNA. Understanding molecular structure and reactivity is fundamental to all chemical safety assessment.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Molecule
Formula Smallest particle of an element/compound; N_A = 6.022×10²³ molecules/mol
Synonyms Molecular unit, chemical molecule, covalent molecule, polyatomic molecule

Frequently Asked Questions

The smallest unit of a covalent compound that retains its chemical identity. Molecules consist of two or more atoms held together by covalent bonds. Diatomic molecules (H₂, O₂, N₂) contain two atoms; polyatomic molecules contain more than two atoms.

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