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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]
The similarity-based [4] virtual screening (a kind of ligand-based virtual screening) assumes that all compounds in a database that are similar to a query compound have similar biological activity. Although this hypothesis is not always valid, [ 5 ] quite often the set of retrieved compounds is considerably enriched with actives. [ 6 ]
A period on the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor. Arranged this way, elements in the same group (column) have similar chemical and physical properties, reflecting the periodic law.
1.3 – synthetic unknown phase 101 Md Mendelevium: Dmitri Mendeleev, Russian chemist who proposed the periodic table: f-block groups 7 f-block [258] (10.3) (1100) – – 1.3 – synthetic unknown phase 102 No Nobelium: Alfred Nobel, Swedish chemist and engineer f-block groups 7 f-block [259] (9.9) (1100) – – 1.3 – synthetic unknown ...
There are 18 numbered groups in the periodic table; the 14 f-block columns, between groups 2 and 3, are not numbered. The elements in a group have similar physical or chemical characteristics of the outermost electron shells of their atoms (i.e., the same core charge), because most chemical properties are dominated by the orbital location of ...
For example, Li + is a small cation with a +1 charge and Mg 2+ is somewhat larger with a +2 charge, so the ionic potential of each of the two ions is roughly the same. It was revealed by an examination that the charge density of lithium is much closer to that of magnesium than to those of the other alkali metals. [ 3 ]
This is a list of chemical elements and their atomic properties, ordered by atomic number (Z).. Since valence electrons are not clearly defined for the d-block and f-block elements, there not being a clear point at which further ionisation becomes unprofitable, a purely formal definition as number of electrons in the outermost shell has been used.
Scandium comes from the Latin word for Scandinavia. Thulium is from the Ancient Greek word for the remote Arctic land that the Romans called ultima Thule. [24] [28] A number of other elements are named after classical words for various places. Ruthenium is from the Latin name for the region including Belarus, Ukraine, and Russia. [29]