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Pa Protactinium
Element Information, Facts, Properties, Trends, Uses, Comparison with other elements

91
Pa
Protactinium
Element 91 of Periodic table is Protactinium with atomic number 91, atomic weight 231.03588. Protactinium, symbol Pa, has a Centered Tetragonal structure and Silver color. Protactinium is a Actinide element. It is part of group null (). Know everything about Protactinium Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.
91 Pa - Protactinium | SchoolMyKids

Protactinium is a chemical element with symbol Pa and atomic number 91. It is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. It forms various chemical compounds where protactinium is usually present in the oxidation state +5, but can also assume +4 and even +2 or +3 states.

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

Protactinium Facts

Read key information and facts about element Protactinium

NameProtactinium
Atomic Number91
Atomic SymbolPa
Atomic Weight231.03588
PhaseSolid
ColorSilver
Appearancebright, silvery metallic luster
ClassificationActinide
Group in Periodic Table-
Group Name
Period in Periodic Tableperiod 7
Block in Periodic Tablef -block
Electronic Configuration[Rn] 5f2 6d1 7s2
Electronic Shell Structure (Electrons per shell)2, 8, 18, 32, 20, 9, 2
Melting Point1845 K
Boiling Point4273 K
CAS NumberCAS7440-13-3
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 Protactinium 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 91 to find Protactinium 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 Protactinium on periodic table look for cross section of group - and period 7 in the modern periodic table.

Protactinium History

The element Protactinium was discovered by O. H. Göhring and K. Fajans in year 1913 in Germany and United Kingdom. Protactinium was first isolated by A. von Grosse in 1927. Protactinium derived its name from the Greek protos, 'first', and actinium, which is produced through the radioactive decay of protactinium.

The two obtained the first isotope of this element that had been predicted by Mendeleev in 1871 as a member of the natural decay of 238U. Originally isolated in 1900 by William Crookes, who nevertheless did not recognize that it was a new element.

Protactinium Presence: Abundance in Nature and Around Us

The table below shows the abundance of Protactinium 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 Crust0.0000100.0000009
Abundance in Oceans0.00000000000000020.000000000000000005
Abundance in Humans--

Crystal Structure of Protactinium

The solid state structure of Protactinium is Centered Tetragonal.

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
392.5 pm392.5 pm323.8 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 NameI4/mmm 91 Pa Protactinium - Crystal Structure | SchoolMyKids
Oxidation StatesSpace Group Number139
Crystal StructureCentered Tetragonal

Protactinium Atomic and Orbital Properties

Protactinium atoms have 91 electrons and the electronic shell structure is [2, 8, 18, 32, 20, 9, 2] with Atomic Term Symbol (Quantum Numbers) 4K11/2.

Atomic Number91
Number of Electrons (with no charge)91
Number of Protons91
Mass Number231
Number of Neutrons140
Shell structure (Electrons per energy level)2, 8, 18, 32, 20, 9, 2
Electron Configuration[Rn] 5f2 6d1 7s2
Valence Electrons5f2 6d1 7s2
Valence (Valency)5
Main Oxidation States5
Oxidation States2, 3, 4, 5
Atomic Term Symbol (Quantum Numbers)4K11/2

Bohr Atomic Model of Protactinium - Electrons per energy level

91 Pa Protactinium - Electron Shell Structure | SchoolMyKids
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Ground State Electronic Configuration of Protactinium - neutral Protactinium atom

Abbreviated electronic configuration of Protactinium

The ground state abbreviated electronic configuration of Neutral Protactinium atom is [Rn] 5f2 6d1 7s2. The portion of Protactinium 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 5f2 6d1 7s2, electrons in the outermost shell that determine the chemical properties of the element.

Unabbreviated electronic configuration of neutral Protactinium

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

1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f2 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 Protactinium
    Atomic Structure of Protactinium

    Protactinium 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 Volume15.18 cm3/mol
    Covalent Radius-
    Van der Waals Radius-
    Neutron Cross Section500
    Neutron Mass Absorption -

    Atomic Spectrum of Protactinium

    Atomic Spectrum of Protactinium | SchoolMyKids

    Protactinium Chemical Properties: Protactinium Ionization Energies and electron affinity

    The electron affinity of Protactinium is - .

    Valence5
    Electronegativity1.5
    ElectronAffinity-

    Ionization Energy of Protactinium

    Refer to table below for Ionization energies of Protactinium

    Ionization energy numberEnthalpy - kJ/mol
    1st568

    Protactinium Physical Properties

    Refer to below table for Protactinium Physical Properties

    Density15.37 g/cm3
    Molar Volume15.18 cm3/mol

    Elastic Properties

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

    Hardness of Protactinium - Tests to Measure of Hardness of Element

    Mohs Hardness-
    Vickers Hardness-
    Brinell Hardness-

    Protactinium Electrical Properties

    Protactinium is Conductor of electricity. Refer to table below for the Electrical properties ofProtactinium

    Electrical Conductivity5600000 S/m
    Resistivity1.8e-7 m Ω
    Superconducting Point1.4

    Protactinium Heat and Conduction Properties

    Thermal Conductivity47 W/(m K)
    Thermal Expansion-

    Protactinium Magnetic Properties

    Magnetic TypeParamagnetic
    Curie Point-
    Mass Magnetic Susceptibility3.25e-8 m3/kg
    Molar Magnetic Susceptibility7.509e-9 m3/mol
    Volume Magnetic Susceptibility0.0004995

    Optical Properties of Protactinium

    Refractive Index-

    Acoustic Properties of Protactinium

    Speed of Sound-

    Protactinium Thermal Properties - Enthalpies and thermodynamics

    Refer to table below for Thermal properties of Protactinium

    Melting Point1845 K (1571.85°C, 2861.33 °F)
    Boiling Point4273 K (3999.85°C, 7231.7300000000005 °F)
    Critical Temperature-
    Superconducting Point1.4

    Enthalpies of Protactinium

    Heat of Fusion15 kJ/mol
    Heat of Vaporization470 kJ/mol
    Heat of Combustion-

    Protactinium Isotopes - Nuclear Properties of Protactinium

    Protactinium has 29 isotopes, with between 212 and 240 nucleons. Protactinium has 0 stable naturally occuring isotopes.

    Isotopes of Protactinium - Naturally occurring stable Isotopes: -.

    IsotopeZNIsotope Mass% AbundanceT halfDecay Mode
    212Pa91121212Synthetic
    213Pa91122213Synthetic
    214Pa91123214Synthetic
    215Pa91124215Synthetic
    216Pa91125216Synthetic
    217Pa91126217Synthetic
    218Pa91127218Synthetic
    219Pa91128219Synthetic
    220Pa91129220Synthetic
    221Pa91130221Synthetic
    222Pa91131222Synthetic
    223Pa91132223Synthetic
    224Pa91133224Synthetic
    225Pa91134225Synthetic
    226Pa91135226Synthetic
    227Pa91136227Synthetic
    228Pa91137228Synthetic
    229Pa91138229Synthetic
    230Pa91139230Synthetic
    231Pa91140231Synthetic32788 yearsAlphaEmission
    232Pa91141232Synthetic
    233Pa91142233Synthetic
    234Pa91143234Synthetic
    235Pa91144235Synthetic
    236Pa91145236Synthetic
    237Pa91146237Synthetic
    238Pa91147238Synthetic
    239Pa91148239Synthetic
    240Pa91149240Synthetic

    Database Search

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

    DatabaseIdentifier number
    CAS Number - Chemical Abstracts Service (CAS)CAS7440-13-3
    RTECS Number-
    CID Number -
    Gmelin Number-
    NSC Number-

    Compare Protactinium with other elements

    Compare Protactinium with all Group elements

    Compare Protactinium with all Period 7 elements

    Compare Protactinium with all Actinide elements