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Ac Actinium
Element Information, Facts, Properties, Trends, Uses, Comparison with other elements

89
Ac
Actinium
Element 89 of Periodic table is Actinium with atomic number 89, atomic weight 227. Actinium, symbol Ac, has a Face Centered Cubic structure and Silver color. Actinium is a Actinide element. It is part of group null (). Know everything about Actinium Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.
89 Ac - Actinium | SchoolMyKids

Actinium is a radioactive chemical element with symbol Ac (not to be confused with the abbreviation for an acetyl group) and atomic number 89, which was discovered in 1899. It was the first non-primordial radioactive element to be isolated. Polonium, radium and radon were observed before actinium, but they were not isolated until 1902.

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

Actinium Facts

Read key information and facts about element Actinium

NameActinium
Atomic Number89
Atomic SymbolAc
Atomic Weight227
PhaseSolid
ColorSilver
Appearance-
ClassificationActinide
Group in Periodic Table-
Group Name
Period in Periodic Tableperiod 7
Block in Periodic Tablef -block
Electronic Configuration[Rn] 6d1 7s2
Electronic Shell Structure (Electrons per shell)2, 8, 18, 32, 18, 9, 2
Melting Point1323 K
Boiling Point3473 K
CAS NumberCAS7440-34-8
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 Actinium 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 89 to find Actinium 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 Actinium on periodic table look for cross section of group - and period 7 in the modern periodic table.

Actinium History

The element Actinium was discovered by F. O. Giesel in year 1902 in France. Actinium was first isolated by F. O. Giesel in 1902. Actinium derived its name from the Greek aktis, 'ray'.

Giesel obtained from pitchblende a substance that had properties similar to those of lanthanum and named itemanium. André-Louis Debiernehad previously reported the discovery of a new element actinium that was supposedly similar to titanium and thorium; the elements were mistakenly identified as being identical and Debierne's name was chosen, even though in retrospect Debierne's substance could not have included much actual element 89.

Actinium Presence: Abundance in Nature and Around Us

The table below shows the abundance of Actinium 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 Universe--
Abundance in Sun--
Abundance in Meteorites--
Abundance in Earth's Crust--
Abundance in Oceans--
Abundance in Humans--

Crystal Structure of Actinium

The solid state structure of Actinium 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
567 pm567 pm567 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 89 Ac Actinium - Crystal Structure | SchoolMyKids
Oxidation StatesSpace Group Number225
Crystal StructureFace Centered Cubic

Actinium Atomic and Orbital Properties

Actinium atoms have 89 electrons and the electronic shell structure is [2, 8, 18, 32, 18, 9, 2] with Atomic Term Symbol (Quantum Numbers) 2D3/2.

Atomic Number89
Number of Electrons (with no charge)89
Number of Protons89
Mass Number227
Number of Neutrons138
Shell structure (Electrons per energy level)2, 8, 18, 32, 18, 9, 2
Electron Configuration[Rn] 6d1 7s2
Valence Electrons6d1 7s2
Valence (Valency)3
Main Oxidation States3
Oxidation States2, 3
Atomic Term Symbol (Quantum Numbers)2D3/2

Bohr Atomic Model of Actinium - Electrons per energy level

89 Ac Actinium - Electron Shell Structure | SchoolMyKids
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Ground State Electronic Configuration of Actinium - neutral Actinium atom

Abbreviated electronic configuration of Actinium

The ground state abbreviated electronic configuration of Neutral Actinium atom is [Rn] 6d1 7s2. The portion of Actinium 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 6d1 7s2, electrons in the outermost shell that determine the chemical properties of the element.

Unabbreviated electronic configuration of neutral Actinium

Complete ground state electronic configuration for the Actinium atom, Unabbreviated electronic configuration

1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 6d1 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 Actinium
    Atomic Structure of Actinium

    Actinium atomic radius is 195 pm, while it's covalent radius is - .

    Atomic Radius Calculated

    195 pm (1.95 Å)

    Atomic Radius Empirical

    195 pm (1.95 Å)

    Atomic Volume22.5422 cm3/mol
    Covalent Radius-
    Van der Waals Radius-
    Neutron Cross Section810
    Neutron Mass Absorption 0.079

    Atomic Spectrum of Actinium

    Atomic Spectrum of Actinium | SchoolMyKids

    Actinium Chemical Properties: Actinium Ionization Energies and electron affinity

    The electron affinity of Actinium is - .

    Valence3
    Electronegativity1.1
    ElectronAffinity-

    Ionization Energy of Actinium

    Refer to table below for Ionization energies of Actinium

    Ionization energy numberEnthalpy - kJ/mol
    1st499
    2nd1170

    Actinium Physical Properties

    Refer to below table for Actinium Physical Properties

    Density10.07 g/cm3
    Molar Volume22.5422 cm3/mol

    Elastic Properties

    Young Modulus-
    Shear Modulus-
    Bulk Modulus -
    Poisson Ratio-

    Hardness of Actinium - Tests to Measure of Hardness of Element

    Mohs Hardness-
    Vickers Hardness-
    Brinell Hardness-

    Actinium Electrical Properties

    Actinium is Conductor of electricity. Refer to table below for the Electrical properties ofActinium

    Electrical Conductivity-
    Resistivity-
    Superconducting Point-

    Actinium Heat and Conduction Properties

    Thermal Conductivity12 W/(m K)
    Thermal Expansion-

    Actinium Magnetic Properties

    Magnetic Type-
    Curie Point-
    Mass Magnetic Susceptibility-
    Molar Magnetic Susceptibility-
    Volume Magnetic Susceptibility-

    Optical Properties of Actinium

    Refractive Index-

    Acoustic Properties of Actinium

    Speed of Sound-

    Actinium Thermal Properties - Enthalpies and thermodynamics

    Refer to table below for Thermal properties of Actinium

    Melting Point1323 K (1049.85°C, 1921.73 °F)
    Boiling Point3473 K (3199.85°C, 5791.73 °F)
    Critical Temperature-
    Superconducting Point-

    Enthalpies of Actinium

    Heat of Fusion14 kJ/mol
    Heat of Vaporization400 kJ/mol
    Heat of Combustion-

    Actinium Isotopes - Nuclear Properties of Actinium

    Actinium has 31 isotopes, with between 206 and 236 nucleons. Actinium has 0 stable naturally occuring isotopes.

    Isotopes of Actinium - Naturally occurring stable Isotopes: -.

    IsotopeZNIsotope Mass% AbundanceT halfDecay Mode
    206Ac89117206Synthetic
    207Ac89118207Synthetic
    208Ac89119208Synthetic
    209Ac89120209Synthetic
    210Ac89121210Synthetic
    211Ac89122211Synthetic
    212Ac89123212Synthetic
    213Ac89124213Synthetic
    214Ac89125214Synthetic
    215Ac89126215Synthetic
    216Ac89127216Synthetic
    217Ac89128217Synthetic
    218Ac89129218Synthetic
    219Ac89130219Synthetic
    220Ac89131220Synthetic
    221Ac89132221Synthetic
    222Ac89133222Synthetic
    223Ac89134223Synthetic
    224Ac89135224Synthetic
    225Ac89136225Synthetic
    226Ac89137226Synthetic
    227Ac89138227Synthetic21.7865 yearsBetaDecay
    228Ac89139228Synthetic
    229Ac89140229Synthetic
    230Ac89141230Synthetic
    231Ac89142231Synthetic
    232Ac89143232Synthetic
    233Ac89144233Synthetic
    234Ac89145234Synthetic
    235Ac89146235Synthetic
    236Ac89147236Synthetic

    Database Search

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

    DatabaseIdentifier number
    CAS Number - Chemical Abstracts Service (CAS)CAS7440-34-8
    RTECS Number-
    CID Number -
    Gmelin Number-
    NSC Number-

    Compare Actinium with other elements

    Compare Actinium with all Group elements

    Compare Actinium with all Period 7 elements

    Compare Actinium with all Actinide elements