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The concept of chemical similarity can be expanded to consider chemical similarity network theory, where descriptive network properties and graph theory can be applied to analyze large chemical space, estimate chemical diversity and predict drug target. Recently, 3D chemical similarity networks based on 3D ligand conformation have also been ...
There are currently 118 known chemical elements with a wide range of physical and chemical properties. Amongst this diversity, scientists have found it useful to apply names for various sets of elements that have similar properties, to varying degrees. Many of these sets are formally recognized by the standards body IUPAC. [1]
Arranged this way, elements in the same group (column) have similar chemical and physical properties, reflecting the periodic law. For example, the halogens lie in the second-to-last group ( group 17 ) and share similar properties, such as high reactivity and the tendency to gain one electron to arrive at a noble-gas electronic configuration.
On the periodic table, homologous elements share many electrochemical properties and appear in the same group (column) of the table. For example, all noble gases are colorless, monatomic gases with very low reactivity. These similarities are due to similar structure in their outer shells of valence electrons. [10]
Thus, on both descending a period and crossing a group by one element, the changes "cancel" each other out, and elements with similar properties which have similar chemistry are often found – the atomic radius, electronegativity, properties of compounds (and so forth) of the diagonal members are similar.
The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). [1] The elements have very similar properties: they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure. [2]
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.
The first two members of the group share similar properties as they are solid metals under standard conditions. Mercury is the only metal that is known to be a liquid at room temperature – as copernicium's boiling point has not yet been measured accurately enough, [ note 2 ] it is not yet known whether it is a liquid or a gas under standard ...