F-block
Encyclopedia
The f-block of the periodic table
of the elements
consists of those elements whose atoms or ions have valence electrons in f-orbital
s. Actual electronic configurations
may be slightly different from what is predicted by the Aufbau principle
. The elements are also known as inner transition elements, although that term is normally taken to include lutetium and lawrencium
as well, which are part of the d-block
.
All elements in the lanthanide series form M3+ ions. In aqueous solution the early lanthanides are surrounded by nine water molecules while the later lanthanides have a coordination number
of 8. Cerium
also forms compounds with the +4 oxidation state
; Ce4+ has the very stable electronic configuration of the noble gas xenon
. Ce(IV) is a strong oxidising agent. Eu2+
has the configuration [Xe]4f7 and is a strong reducing agent. The existence of Eu(II) is attributed to the stability of the half-filled f-shell.
Periodic table
The periodic table of the chemical elements is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasing atomic number, the number of protons in an atom's atomic nucleus...
of the elements
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
consists of those elements whose atoms or ions have valence electrons in f-orbital
Atomic orbital
An atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom. This function can be used to calculate the probability of finding any electron of an atom in any specific region around the atom's nucleus...
s. Actual electronic configurations
Periodic table (electron configurations)
* Configurations of elements 105 and above are uncertain or not available.* Grayed out electron numbers indicate subshells that are filled to their maximum....
may be slightly different from what is predicted by the Aufbau principle
Aufbau principle
The Aufbau principle is used to determine the electron configuration of an atom, molecule or ion. The principle postulates a hypothetical process in which an atom is "built up" by progressively adding electrons...
. The elements are also known as inner transition elements, although that term is normally taken to include lutetium and lawrencium
Lawrencium
Lawrencium is a radioactive synthetic chemical element with the symbol Lr and atomic number 103. In the periodic table of the elements, it is a period 7 d-block element and the last element of actinide series...
as well, which are part of the d-block
D-block
The d-block is the portion of the periodic table that contains the element groups 3-12. These groups correspond to the filling of the atomic d-orbital subshell, with electron configurations ranging from s2d1 to s2d10...
.
| * Lanthanoids Lanthanide The lanthanide or lanthanoid series comprises the fifteen metallic chemical elements with atomic numbers 57 through 71, from lanthanum through lutetium... |
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| ** Actinoids Actinide The actinide or actinoid series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium.The actinide series derives its name from the group 3 element actinium... |
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All elements in the lanthanide series form M3+ ions. In aqueous solution the early lanthanides are surrounded by nine water molecules while the later lanthanides have a coordination number
Coordination number
In chemistry and crystallography, the coordination number of a central atom in a molecule or crystal is the number of its nearest neighbours. This number is determined somewhat differently for molecules and for crystals....
of 8. Cerium
Cerium
Cerium is a chemical element with the symbol Ce and atomic number 58. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet . Cerium is the most abundant of the rare earth elements, making up about 0.0046% of the Earth's crust by weight...
also forms compounds with the +4 oxidation state
Oxidation state
In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...
; Ce4+ has the very stable electronic configuration of the noble gas xenon
Xenon
Xenon is a chemical element with the symbol Xe and atomic number 54. The element name is pronounced or . A colorless, heavy, odorless noble gas, xenon occurs in the Earth's atmosphere in trace amounts...
. Ce(IV) is a strong oxidising agent. Eu2+
Europium
Europium is a chemical element with the symbol Eu and atomic number 63. It is named after the continent of Europe. It is a moderately hard silvery metal which readily oxidizes in air and water...
has the configuration [Xe]4f7 and is a strong reducing agent. The existence of Eu(II) is attributed to the stability of the half-filled f-shell.
External links
- Images of f-orbitals
- Interactive f-orbital models can be found at this site:http://www.d.umn.edu/~pkiprof/ChemWebV2/AOs/ao4.html