Chemical compound

A pure substance whose atoms of two or more different elements are chemically bonded in fixed proportions. Its composition and properties distinguish it from mixtures and from the elements it contains.

Chemical bond: An attractive interaction that holds atoms or ions together in a chemical substance. Chemical bonds join atoms of different elements into compounds.
Mixture: Matter composed of two or more substances physically combined without fixed chemical proportions. Unlike a compound, a mixture can vary in composition and be separated physically.
Ionic bonding: Electrostatic attraction between oppositely charged ions, commonly formed by electron transfer. Ionic bonding builds compounds such as sodium chloride from charged particles.
Water: A chemical compound with formula H₂O, whose molecules contain two hydrogen atoms bonded to one oxygen atom. Water is a familiar molecular compound with distinctive solvent and physical properties.
Robert Boyle: A seventeenth-century natural philosopher whose work helped establish experimental chemistry. Boyle challenged older ideas about elements and encouraged analysis of material substances.
Chemical formula: A symbolic expression showing which elements a substance contains and, often, their relative amounts. Formulas encode the fixed elemental proportions that identify a compound.
Homogeneous mixture: A mixture with uniform composition throughout, such as a salt solution. Its uniform appearance does not make it a compound; its components remain mixed.
Covalent bond: A chemical bond formed when atoms share electron pairs. Covalent bonds connect atoms in molecular compounds and extended networks.
Sodium chloride: An ionic compound with formula NaCl, composed of sodium and chloride ions. Table salt illustrates a compound whose formula unit is not a discrete molecule.
Antoine Lavoisier: An eighteenth-century French chemist who helped establish modern chemical nomenclature and conservation of mass. His systematic approach made the composition of compounds measurable and communicable.

Linked from 8 pages