* Chemical Bonding: Compounds are formed by the chemical combination of two or more elements in a fixed ratio. This combination involves the sharing or transfer of electrons, creating entirely new chemical bonds and structures.
* New Properties Emerge: The bonds and structures formed in compounds lead to the emergence of entirely new properties. These properties are not simply the sum of the properties of the individual elements.
Examples:
* Water (H₂O): Hydrogen (H) is a flammable gas, and oxygen (O) is a gas that supports combustion. When combined, they form water, a liquid that is essential for life and extinguishes fire.
* Sodium Chloride (NaCl): Sodium (Na) is a highly reactive metal, and chlorine (Cl) is a toxic gas. When combined, they form sodium chloride, or table salt, a stable, edible compound.
Key Points:
* Compounds are formed by chemical reactions, not just physical mixtures.
* The properties of a compound are determined by the way the atoms of its constituent elements are bonded together.
* You cannot predict the properties of a compound based solely on the properties of its elements.
