Definitions of Atoms and Molecules
Atoms are the smallest units of an element that retain its chemical properties, consisting of a nucleus with protons and neutrons surrounded by electrons. Molecules are groups of two or more atoms bonded together, forming the smallest unit of a compound that retains its composition and properties.
Key Components and Structure
The structure of an atom includes positively charged protons and neutral neutrons in the nucleus, with negatively charged electrons orbiting in shells. Molecules form through chemical bonds, such as covalent bonds where atoms share electrons, or ionic bonds where electrons are transferred, determining the molecule's stability and reactivity.
Practical Examples
A single hydrogen atom (H) exemplifies an atom, containing one proton and one electron. A water molecule (H₂O) is a common example of a molecule, where two hydrogen atoms bond with one oxygen atom, enabling water's liquid state and solvent properties essential for life.
Importance and Real-World Applications
Atoms and molecules form all visible matter, from air to solids, underpinning fields like materials science, medicine, and environmental studies. Understanding them allows scientists to design drugs, develop new materials, and model chemical reactions in industries such as pharmaceuticals and energy production.