Allotropes / Allotropy. Isotopes. Atomic Mass and Atomic Weight. Atomic Number. List of elements. Periodic table. Standard 18-column form of the periodic table. The colors used in the version of the table shown here signify different categories of elements, as listed below in the Layout section, under the larger table. The rows of the table are called periods; the columns are called groups, with some of these having names such as halogens or noble gases. Since, by definition, a periodic table incorporates recurring trends, any such table can be used to derive relationships between the properties of the elements and predict the properties of new, yet to be discovered or synthesized, elements. As a result, a periodic table—whether in the standard form or some other variant—provides a useful framework for analyzing chemical behavior, and such tables are widely used in chemistry and other sciences. Although precursors exist, Dmitri Mendeleev is generally credited with the publication, in 1869, of the first widely recognized periodic table.
Layout Grouping methods Groups Periods Blocks Categories Atomic radii. Periodic_table. Chemical element. Chemistry. Chemistry, a branch of physical science, is the study of the composition, structure, properties and change of matter.[1][2] Chemistry is chiefly concerned with atoms and their interactions with other atoms - for example, the properties of the chemical bonds formed between atoms to create chemical compounds. As well as this, interactions including atoms and other phenomena - electrons and various forms of energy—are considered, such as photochemical reactions, oxidation-reduction reactions, changes in phases of matter, and separation of mixtures. Finally, properties of matter such as alloys or polymers are considered.
Chemistry is sometimes called "the central science" because it bridges other natural sciences like physics, geology and biology with each other.[3][4] Chemistry is a branch of physical science but distinct from physics.[5] Etymology The word alchemy in turn is derived from the Arabic word al-kīmīā (الکیمیاء). Definition History Chemistry as science Chemical structure Matter Atom.