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Th Thorium
Element Information, Facts, Properties, Trends, Uses, Comparison with other elements

90
Th
Thorium
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. It is part of group null (). Know everything about Thorium Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.
90 Th - Thorium | SchoolMyKids

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.

It belongs to group of the periodic table having trivial name .

Thorium Facts

Read key information and facts about element Thorium

NameThorium
Atomic Number90
Atomic SymbolTh
Atomic Weight232.0381
PhaseSolid
ColorSilver
Appearancesilvery, often with black tarnish
ClassificationActinide
Group in Periodic Table-
Group Name
Period in Periodic Tableperiod 7
Block in Periodic Tablef -block
Electronic Configuration[Rn] 6d2 7s2
Electronic Shell Structure (Electrons per shell)2, 8, 18, 32, 18, 10, 2
Melting Point2023 K
Boiling Point5093 K
CAS NumberCAS7440-29-1
Neighborhood Elements
123456789101112131415161718
1
1
H
Hydrogen
1.008

Atomic #

Electronic Shell #

Symbol
Name
Atomic Weight
HGas
HgLiquid
CSolid
Metals
Metalloids
NonMetals
Alkali metals
Alkali earth metals
Lanthanoids
Transition metals
Post-transition metals
Other nonmetals
Halogens
Nobel gas
Actinoids
2
He
Helium
4.003
2
3
Li
Lithium
6.941
4
Be
Beryllium
9.012
5
B
Boron
10.811
6
C
Carbon
12.011
7
N
Nitrogen
14.007
8
O
Oxygen
15.999
9
F
Fluorine
18.998
10
Ne
Neon
20.180
3
11
Na
Sodium
22.990
12
Mg
Magnesium
24.305
13
Al
Aluminium
26.982
14
Si
Silicon
28.085
15
P
Phosphorus
30.974
16
S
Sulfur
32.065
17
Cl
Chlorine
35.453
18
Ar
Argon
39.948
4
19
K
Potassium
39.098
20
Ca
Calcium
40.078
21
Sc
Scandium
44.956
22
Ti
Titanium
47.867
23
V
Vanadium
50.941
24
Cr
Chromium
51.996
25
Mn
Manganese
54.938
26
Fe
Iron
55.845
27
Co
Cobalt
58.933
28
Ni
Nickel
58.693
29
Cu
Copper
63.546
30
Zn
Zinc
65.409
31
Ga
Gallium
69.723
32
Ge
Germanium
72.640
33
As
Arsenic
74.922
34
Se
Selenium
78.960
35
Br
Bromine
79.904
36
Kr
Krypton
83.798
5
37
Rb
Rubidium
85.468
38
Sr
Strontium
87.620
39
Y
Yttrium
88.906
40
Zr
Zirconium
91.224
41
Nb
Niobium
92.906
42
Mo
Molybdenum
95.940
43
Tc
Technetium
98
44
Ru
Ruthenium
101.070
45
Rh
Rhodium
102.906
46
Pd
Palladium
106.420
47
Ag
Silver
107.868
48
Cd
Cadmium
112.411
49
In
Indium
114.818
50
Sn
Tin
118.710
51
Sb
Antimony
121.760
52
Te
Tellurium
127.600
53
I
Iodine
126.904
54
Xe
Xenon
131.293
6
55
Cs
Cesium
132.905
56
Ba
Barium
137.327
57 - 71
La - Lu
Lanthanides
72
Hf
Hafnium
178.490
73
Ta
Tantalum
180.948
74
W
Tungsten
183.840
75
Re
Rhenium
186.207
76
Os
Osmium
190.230
77
Ir
Iridium
192.217
78
Pt
Platinum
195.078
79
Au
Gold
196.967
80
Hg
Mercury
200.590
81
Tl
Thallium
204.383
82
Pb
Lead
207.200
83
Bi
Bismuth
208.980
84
Po
Polonium
209
85
At
Astatine
210
86
Rn
Radon
222
7
87
Fr
Francium
223
88
Ra
Radium
226
89 - 103
Ac - Lr
Actinides
104
Rf
Rutherfordium
261
105
Db
Dubnium
262
106
Sg
Seaborgium
266
107
Bh
Bohrium
264
108
Hs
Hassium
277
109
Mt
Meitnerium
268
110
Ds
Darmstadtium
281
111
Rg
Roentgenium
272
112
Cn
Copernicium
285
113
Nh
Nihonium
284
114
Fl
Flerovium
289
115
Mc
Moscovium
288
116
Lv
Livermorium
292
117
Ts
Tennessine
294
118
Og
Oganesson
294
Lanthanides
57
La
Lanthanum
138.905
58
Ce
Cerium
140.116
59
Pr
Praseodymium
140.908
60
Nd
Neodymium
144.240
61
Pm
Promethium
145
62
Sm
Samarium
150.360
63
Eu
Europium
151.964
64
Gd
Gadolinium
157.250
65
Tb
Terbium
158.925
66
Dy
Dysprosium
162.500
67
Ho
Holmium
164.930
68
Er
Erbium
167.259
69
Tm
Thulium
168.934
70
Yb
Ytterbium
173.040
71
Lu
Lutetium
174.967
Actinides
89
Ac
Actinium
227
90
Th
Thorium
232.038
91
Pa
Protactinium
231.036
92
U
Uranium
238.029
93
Np
Neptunium
237
94
Pu
Plutonium
244
95
Am
Americium
243
96
Cm
Curium
247
97
Bk
Berkelium
247
98
Cf
Californium
251
99
Es
Einsteinium
252
100
Fm
Fermium
257
101
Md
Mendelevium
258
102
No
Nobelium
259
103
Lr
Lawrencium
262

How to Locate Thorium on Periodic Table

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 - and period 7 in the modern periodic table.

Thorium History

The element Thorium was discovered by J. Berzelius in year 1829 in Sweden. Thorium was first isolated by D. Lely, Jr. and L. Hamburger in 1914. Thorium derived its name from Thor, the Scandinavian god of thunder.

Berzelius obtained the oxide of a new earth inthorite.

Thorium Presence: Abundance in Nature and Around Us

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 %)ppb by atoms (1ppb =10^-7 %)
Abundance in Universe0.40.002
Abundance in Sun0.30.002
Abundance in Meteorites403
Abundance in Earth's Crust6000540
Abundance in Oceans0.000040.0000011
Abundance in Humans--

Crystal Structure of Thorium

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.

Unit Cell Parameters

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)

abc
508.42 pm508.42 pm508.42 pm

and the angles between them Lattice Angles (alpha, beta and gamma).

alphabetagamma
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 NameFm_ 3m 90 Th Thorium - Crystal Structure | SchoolMyKids
Oxidation StatesSpace Group Number225
Crystal StructureFace Centered Cubic

Thorium Atomic and Orbital Properties

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 Number90
Number of Electrons (with no charge)90
Number of Protons90
Mass Number232
Number of Neutrons142
Shell structure (Electrons per energy level)2, 8, 18, 32, 18, 10, 2
Electron Configuration[Rn] 6d2 7s2
Valence Electrons6d2 7s2
Valence (Valency)4
Main Oxidation States4
Oxidation States-1, 1, 2, 3, 4
Atomic Term Symbol (Quantum Numbers)3F2

Bohr Atomic Model of Thorium - Electrons per energy level

90 Th Thorium - Electron Shell Structure | SchoolMyKids
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Ground State Electronic Configuration of Thorium - neutral Thorium atom

Abbreviated electronic configuration of Thorium

The ground state abbreviated 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.

Unabbreviated electronic configuration of neutral Thorium

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

Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.

  • As per the Aufbau principle the electrons will occupy the orbitals having lower energies before occupying higher energy orbitals. According to this principle, electrons are filled in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…
  • The Pauli exclusion principle states that a maximum of two electrons, each having opposite spins, can fit in an orbital.
  • Hund's rule states that every orbital in a given subshell is singly occupied by electrons before a second electron is filled in an orbital.
  • Electron configuration of Thorium
    Atomic Structure of Thorium

    Thorium atomic radius is 180 pm, while it's covalent radius is - .

    Atomic Radius Calculated

    180 pm (1.8 Å)

    Atomic Radius Empirical

    180 pm (1.8 Å)

    Atomic Volume19.7917 cm3/mol
    Covalent Radius-
    Van der Waals Radius-
    Neutron Cross Section7.4
    Neutron Mass Absorption 0.001

    Atomic Spectrum of Thorium

    Atomic Spectrum of Thorium | SchoolMyKids

    Thorium Chemical Properties: Thorium Ionization Energies and electron affinity

    The electron affinity of Thorium is - .

    Valence4
    Electronegativity1.3
    ElectronAffinity-

    Ionization Energy of Thorium

    Refer to table below for Ionization energies of Thorium

    Ionization energy numberEnthalpy - kJ/mol
    1st587
    2nd1110
    3rd1930
    4th2780

    Thorium Physical Properties

    Refer to below table for Thorium Physical Properties

    Density11.724 g/cm3
    Molar Volume19.7917 cm3/mol

    Elastic Properties

    Young Modulus79
    Shear Modulus31 GPa
    Bulk Modulus 54 GPa
    Poisson Ratio0.27

    Hardness of Thorium - Tests to Measure of Hardness of Element

    Mohs Hardness3 MPa
    Vickers Hardness350 MPa
    Brinell Hardness400 MPa

    Thorium Electrical Properties

    Thorium is Conductor of electricity. Refer to table below for the Electrical properties ofThorium

    Electrical Conductivity6700000 S/m
    Resistivity1.5e-7 m Ω
    Superconducting Point1.38

    Thorium Heat and Conduction Properties

    Thermal Conductivity54 W/(m K)
    Thermal Expansion0.000011 /K

    Thorium Magnetic Properties

    Magnetic TypeParamagnetic
    Curie Point-
    Mass Magnetic Susceptibility7.2e-9 m3/kg
    Molar Magnetic Susceptibility1.7e-9 m3/mol
    Volume Magnetic Susceptibility0.000084

    Optical Properties of Thorium

    Refractive Index-

    Acoustic Properties of Thorium

    Speed of Sound2490 m/s

    Thorium Thermal Properties - Enthalpies and thermodynamics

    Refer to table below for Thermal properties of Thorium

    Melting Point2023 K (1749.85°C, 3181.73 °F)
    Boiling Point5093 K (4819.85°C, 8707.73 °F)
    Critical Temperature-
    Superconducting Point1.38

    Enthalpies of Thorium

    Heat of Fusion16 kJ/mol
    Heat of Vaporization530 kJ/mol
    Heat of Combustion-

    Thorium Isotopes - Nuclear Properties of Thorium

    Thorium has 30 isotopes, with between 209 and 238 nucleons. Thorium has 1 stable naturally occuring isotopes.

    Isotopes of Thorium - Naturally occurring stable Isotopes: 232Th.

    IsotopeZNIsotope Mass% AbundanceT halfDecay Mode
    209Th90119209Synthetic
    210Th90120210Synthetic
    211Th90121211Synthetic
    212Th90122212Synthetic
    213Th90123213Synthetic
    214Th90124214Synthetic
    215Th90125215Synthetic
    216Th90126216Synthetic
    217Th90127217Synthetic
    218Th90128218Synthetic
    219Th90129219Synthetic
    220Th90130220Synthetic
    221Th90131221Synthetic
    222Th90132222Synthetic
    223Th90133223Synthetic
    224Th90134224Synthetic
    225Th90135225Synthetic
    226Th90136226Synthetic
    227Th90137227Synthetic
    228Th90138228Synthetic
    229Th90139229Synthetic
    230Th90140230Synthetic
    231Th90141231Synthetic
    232Th90142232100%1.406×10^10 yearsAlphaEmission
    233Th90143233Synthetic
    234Th90144234Synthetic
    235Th90145235Synthetic
    236Th90146236Synthetic
    237Th90147237Synthetic
    238Th90148238Synthetic

    Regulatory and Health - Health and Safety Parameters and Guidelines

    Database Search

    List of unique identifiers to search the element in various chemical registry databases

    DatabaseIdentifier number
    CAS Number - Chemical Abstracts Service (CAS)CAS7440-29-1
    RTECS NumberRTECSXO6400000
    CID Number CID23960
    Gmelin NumberGmelin16314
    NSC Number-

    Compare Thorium with other elements

    Compare Thorium with all Group elements

    Compare Thorium with all Period 7 elements

    Compare Thorium with all Actinide elements