Element 90 of Periodic table is Thorium with atomic number 90, atomic weight 232.0381. Thorium, symbol Th, has a Face Centered Cubic structure and Silver color. Thorium is a actinide element. Know everything about Thorium Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.
Thorium is a chemical element with symbol Th and atomic number 90. A radioactive actinide metal, thorium is one of only two significantly radioactive elements that still occur naturally in large quantities as a primordial element (the other being uranium). It was discovered in 1828 by the Norwegian Reverend and amateur mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jakob Berzelius, who named it after Thor, the Norse god of thunder.
Read key information and facts about element Thorium
Name | Thorium |
Atomic Number | 90 |
Atomic Symbol | Th |
Atomic Weight | 232.0381 |
Phase | Solid |
Color | Silver |
Classification | actinide |
Group in Periodic Table | N/A |
Group Name | |
Period in Periodic Table | 7 |
Block in Periodic Table | f-block |
Electronic Configuration | [Rn] 6d2 7s2 |
Melting Point | 1750 °C |
Boiling Point | 4820 °C |
Electronic Shell Structure | [2, 8, 18, 32, 18, 10, 2] |
CAS Number | CAS7440-29-1 |
Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 90 to find Thorium on periodic table.
Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Thorium on periodic table look for cross section of group N/A and period 7 in the modern periodic table.
The element Thorium was discovered by Jöns Jakob Berzelius in year 1829 in Sweden . Thorium derived its name from Thor, the Scandinavian god of thunder
The table below shows the abundance of Thorium in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.
Ppb by weight (1ppb =10^-7 %) | |
---|---|
Abundance in Universe | 4×10-8% |
Abundance in Sun | 3×10-8% |
Abundance in Meteorites | 3.9×10-6% |
Abundance in Earth's Crust | 6e-06 |
Abundance in Oceans | 4×10-12% |
Abundance in Humans | None |
The solid state structure of Thorium is Face Centered Cubic.
The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.
The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)
a | b | c |
---|---|---|
508.42 | 508.42 | 508.42 pm |
and the angles between them Lattice Angles (alpha, beta and gamma).
alpha | beta | gamma |
---|---|---|
π/2 | π/2 | π/2 |
The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.
The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.
Space Group Name | Fm_ 3m |
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Space Group Number | 225 | |
Crystal Structure | Face Centered Cubic |
Thorium atoms have 90 electrons and the electronic shell structure is [2, 8, 18, 32, 18, 10, 2] with Atomic Term Symbol (Quantum Numbers) 3F2.
Atomic Number | 90 |
Number of Electrons (with no charge) | 90 |
Number of Protons | 90 |
Mass Number | 232 |
Number of Neutrons | 142 |
Shell structure (Electrons per energy level) | [2, 8, 18, 32, 18, 10, 2] |
Electron Configuration | [Rn] 6d2 7s2 |
Valence Electrons | 6d2 7s2 |
Oxidation State | 1;2;3;4 |
Atomic Term Symbol (Quantum Numbers) | 3F2 |
Shell Structure of Thorium - Electrons per energy level
n | s | p | d | f | |
---|---|---|---|---|---|
1 | K | 2 | |||
2 | L | 2 | 6 | ||
3 | M | 2 | 6 | 10 | |
4 | N | 2 | 6 | 10 | 14 |
5 | O | 2 | 6 | 10 | |
6 | P | 2 | 6 | 2 | |
7 | Q | 2 |
The ground state electronic configuration of Neutral Thorium atom is [Rn] 6d2 7s2. The portion of Thorium configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Rn]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used.This is important as it is the Valence electrons 6d2 7s2, electrons in the outermost shell that determine the chemical properties of the element.
Complete ground state electronic configuration for the Thorium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 6d2 7s2
Thorium atomic radius is 180 pm, while it's covalent radius is N/A.
Atomic Radius |
180 pm (1.8 Å) |
Atomic Volume | 19.7917178437 cm3 |
Covalent Radius | N/A |
Van der Waals Radius | N/A |
Neutron Cross Section | 7.4 σa/barns |
The electron affinity of Thorium is N/A
Valence | 4 |
Electronegativity | 1.3 |
ElectronAffinity | N/A |
Refer to table below for Ionization energies of Thorium
Ionization energy number | Enthalpy - kJ/mol |
---|---|
1 | 587 |
2 | 1110 |
3 | 1930 |
4 | 2780 |
Refer to below table for Thorium Physical Properties
Density | 11.724 g/cm3 |
Molar Volume | 19.7917178437 cm3 |
Young Modulus | 79 GPa |
Shear Modulus | 31 GPa |
Bulk Modulus | 54 GPa |
Poisson Ratio | 0.27 |
Mohs Hardness | 3 MPa |
Vickers Hardness | 350 MPa |
Brinell Hardness | 400 MPa |
Thorium is Conductor of electricity. Refer to table below for the Electrical properties of Thorium
Electrical Conductivity | 6.7×106 S/m |
Resistivity | 1.5×10-7 m Ω |
Superconducting Point | 1.38 |
Thermal Conductivity | 54 W/(m K) |
Thermal Expansion | 0.000011 K-1 |
Magnetic Type | Paramagnetic |
Curie Point | N/A |
Mass Magnetic Susceptibility | 7.2×10-9 |
Molar Magnetic Susceptibility | 1.7×10-9 |
Volume Magnetic Susceptibility | 8.4e-05 |
Refractive Index | N/A |
Speed of Sound | 2490 m/s |
Refer to table below for Thermal properties of Thorium
Melting Point | 2023 K (1750 °C) |
Boiling Point | 5093 K (4820 °C) |
Critical Temperature | N/A |
Superconducting Point | 1.38 |
Heat of Fusion | 16 kJ/mol |
Heat of Vaporization | 530 kJ/mol |
Heat of Combustion | N/A |
Isotopes of rhodium. Naturally occurring Thorium has 1 stable isotope - 232Th.
Isotope | Isotope Mass | % Abundance | T half | Decay Mode |
---|---|---|---|---|
209Th | ||||
210Th | ||||
211Th | ||||
212Th | ||||
213Th | ||||
214Th | ||||
215Th | ||||
216Th | ||||
217Th | ||||
218Th | ||||
219Th | ||||
220Th | ||||
221Th | ||||
222Th | ||||
223Th | ||||
224Th | ||||
225Th | ||||
226Th | ||||
227Th | ||||
228Th | ||||
229Th | ||||
230Th | ||||
231Th | ||||
232Th | 100% | Stable | N/A | |
233Th | ||||
234Th | ||||
235Th | ||||
236Th | ||||
237Th | ||||
238Th |
CAS Number | CAS7440-29-1 |
RTECS Number | RTECSXO6400000 |
DOT Hazard Class | 7 |
DOT Numbers | 2975 |
EU Number | EU231-139-7 |
NFPA Fire Rating | N/A |
NFPA Hazards | N/A |
NFPA Health Rating | N/A |
NFPA Reactivity Rating | N/A |
Autoignition Point | 130 °C |
Flashpoint | N/A |
List of unique identifiers to search the element in various chemical registry databases
Database | Identifier number |
---|---|
CAS Number - Chemical Abstracts Service (CAS) | CAS7440-29-1 |
CID Number | CID23960 |
Gmelin Number | Gmelin16314 |
NSC Number | N/A |
RTECS Number | RTECSXO6400000 |
Metalloid |
Nonmetals |
Other Nonmetals | |
Halogens | Noble Gas |
Metals |
|
Alkali Metals | Alkaline Earth Metals |
Transition Metals | Post-Transition Metals |
Lanthanide | Actinide |