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The main group elements are the elements of groups 1, 2, and 13–18 (i.e. the s-block and p-block). [5] The transition elements are the elements of groups 3–12 (i.e. the d-block) – this in particular includes group 12 (although some sources do not include it). [5] The inner transition elements are f-block elements. [2]
3. Colloquially, any compound which, when dissolved in water, yields a pH of less than 7.0. The term "acid" is commonly used to refer to the entire aqueous solution, whereas stricter definitions refer only to the acidic solute. [2] acid anhydride Any chemical compound derived by the removal of water molecules from an acid. Contrast base anhydride.
Building block is a term in chemistry which is used to describe a virtual molecular fragment or a real chemical compound the molecules of which possess reactive functional groups. [1] Building blocks are used for bottom-up modular assembly of molecular architectures: nano-particles , [ 2 ] [ 3 ] metal-organic frameworks , [ 4 ] organic ...
[2] [3] [4] Lutetium (element 71) is also sometimes considered a lanthanide, despite being a d-block element and a transition metal. The informal chemical symbol Ln is used in general discussions of lanthanide chemistry to refer to any lanthanide. [5] All but one of the lanthanides are f-block elements, corresponding to the filling of the 4f ...
Frankland took the view that the valence (he used the term "atomicity") of an element was a single value that corresponded to the maximum value observed. The number of unused valencies on atoms of what are now called the p-block elements is generally even, and Frankland suggested that the unused valencies saturated one another. For example ...
A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O 2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (two hydrogen atoms and one oxygen atom; H 2 O).
The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows ("periods") and columns ("groups"). It is an icon of chemistry and is widely used in physics and other sciences.
Period 4 includes the biologically essential elements potassium and calcium, and is the first period in the d-block with the lighter transition metals. These include iron , the heaviest element forged in main-sequence stars and a principal component of the Earth, as well as other important metals such as cobalt , nickel , and copper .