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A diagram representing at the microscopic level the differences between homogeneous mixtures, heterogeneous mixtures, compounds, and elements. Mixtures can be either homogeneous or heterogeneous: a mixture of uniform composition and in which all components are in the same phase, such as salt in water, is called homogeneous, whereas a mixture of ...
One can subdivide chemical compounds into two main groups: molecules, which includes most organic, polyatomic gases, and organometallic compounds, and nonmolecular species, which includes most purely inorganic compounds. The structures of many reagents are often misunderstood because simplified formulas are presented in reaction schemes whereas ...
Cranberry glass, while appearing homogeneous, is a mixture consisting of glass and colloidal gold particles of about 40 nm in diameter, giving it a red color. All matter consists of various elements and chemical compounds, but these are often intimately mixed together.
Ionic compounds can also be produced from their constituent ions by evaporation of their solvent, precipitation, freezing, a solid-state reaction, or the electron transfer reaction of reactive metals with reactive non-metals, such as halogen gases. Ionic compounds typically have high melting and boiling points, and are hard and brittle.
The binary phase diagram in the above diagram shows the phases of a mixture of two substances in varying concentrations, and . The region labeled " α {\displaystyle \alpha } " is a solid solution, with B {\displaystyle B} acting as the solute in a matrix of A {\displaystyle A} .
Alchemical symbols were used to denote chemical elements and compounds, as well as alchemical apparatus and processes, until the 18th century. Although notation was partly standardized, style and symbol varied between alchemists.
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
Each chemical element has a unique atomic number (Z— for "Zahl", German for "number") representing the number of protons in its nucleus. [4] Each distinct atomic number therefore corresponds to a class of atom: these classes are called the chemical elements. [5] The chemical elements are what the periodic table classifies and organizes.