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I Iodine
Element Information, Facts, Properties, Trends, Uses, Comparison with other elements

53
I
Iodine
Element 53 of Periodic table is Iodine with atomic number 53, atomic weight 126.90447. Iodine, symbol I, has a Base Centered Orthorhombic structure and SlateGray color. Iodine is a Halogens element. It is part of group 17 (fluorine family). Know everything about Iodine Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.
53 I - Iodine | SchoolMyKids

Iodine is a chemical element with symbol I and atomic number 53. The name is from Greek ἰοειδής ioeidēs, meaning violet or purple, due to the color of iodine vapor. Iodine and its compounds are primarily used in nutrition, and industrially in the production of acetic acid and certain polymers.

It belongs to group 17 of the periodic table having trivial name halogens.

Iodine Facts

Read key information and facts about element Iodine

NameIodine
Atomic Number53
Atomic SymbolI
Atomic Weight126.90447
PhaseSolid
ColorSlateGray
Appearancelustrous metallic gray, violet as a gas
ClassificationHalogens
Group in Periodic Table17
Group Namefluorine family
Period in Periodic Tableperiod 5
Block in Periodic Tablep -block
Electronic Configuration[Kr] 4d10 5s2 5p5
Electronic Shell Structure (Electrons per shell)2, 8, 18, 18, 7
Melting Point386.85 K
Boiling Point457.4 K
CAS NumberCAS7553-56-2
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 Iodine 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 53 to find Iodine 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 Iodine on periodic table look for cross section of group 17 and period 5 in the modern periodic table.

Iodine History

The element Iodine was discovered by B. Courtois in year 1811 in France. Iodine was first isolated by B. Courtois in 1811. Iodine derived its name from French iode (after the Greek ioeides, 'violet').

Courtois discovered it in the ashes of seaweed.

Iodine Presence: Abundance in Nature and Around Us

The table below shows the abundance of Iodine 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 Universe10.01
Abundance in Sun--
Abundance in Meteorites26030
Abundance in Earth's Crust49080
Abundance in Oceans602.9
Abundance in Humans20010

Crystal Structure of Iodine

The solid state structure of Iodine is Base Centered Orthorhombic.

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
718.02 pm471.02 pm981.03 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 NameCmca 53 I Iodine - Crystal Structure | SchoolMyKids
Oxidation StatesSpace Group Number64
Crystal StructureBase Centered Orthorhombic

Iodine Atomic and Orbital Properties

Iodine atoms have 53 electrons and the electronic shell structure is [2, 8, 18, 18, 7] with Atomic Term Symbol (Quantum Numbers) 2P3/2.

Atomic Number53
Number of Electrons (with no charge)53
Number of Protons53
Mass Number127
Number of Neutrons74
Shell structure (Electrons per energy level)2, 8, 18, 18, 7
Electron Configuration[Kr] 4d10 5s2 5p5
Valence Electrons5s2 5p5
Valence (Valency)7
Main Oxidation States-1, 1, 3, 5, 7
Oxidation States-1, 1, 2, 3, 4, 5, 6, 7
Atomic Term Symbol (Quantum Numbers)2P3/2

Bohr Atomic Model of Iodine - Electrons per energy level

53 I Iodine - Electron Shell Structure | SchoolMyKids
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Ground State Electronic Configuration of Iodine - neutral Iodine atom

Abbreviated electronic configuration of Iodine

The ground state abbreviated electronic configuration of Neutral Iodine atom is [Kr] 4d10 5s2 5p5. The portion of Iodine configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Kr]. 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 5s2 5p5, electrons in the outermost shell that determine the chemical properties of the element.

Unabbreviated electronic configuration of neutral Iodine

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

1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p5

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 Iodine
    Atomic Structure of Iodine

    Iodine atomic radius is 115 pm, while it's covalent radius is 133 pm.

    Atomic Radius Calculated

    115 pm (1.15 Å)

    Atomic Radius Empirical

    140 pm (1.4 Å)

    Atomic Volume25.689 cm3/mol
    Covalent Radius133 pm (1.33 Å)
    Van der Waals Radius198 pm
    Neutron Cross Section6.2
    Neutron Mass Absorption 0.0018

    Atomic Spectrum of Iodine

    Atomic Spectrum of Iodine | SchoolMyKids

    Iodine Chemical Properties: Iodine Ionization Energies and electron affinity

    The electron affinity of Iodine is 295.2 kJ/mol.

    Valence7
    Electronegativity2.66
    ElectronAffinity295.2 kJ/mol

    Ionization Energy of Iodine

    Refer to table below for Ionization energies of Iodine

    Ionization energy numberEnthalpy - kJ/mol
    1st1008.4
    2nd1845.9
    3rd3180

    Iodine Physical Properties

    Refer to below table for Iodine Physical Properties

    Density4.94 g/cm3
    Molar Volume25.689 cm3/mol

    Elastic Properties

    Young Modulus-
    Shear Modulus-
    Bulk Modulus 7.7 GPa
    Poisson Ratio-

    Hardness of Iodine - Tests to Measure of Hardness of Element

    Mohs Hardness-
    Vickers Hardness-
    Brinell Hardness-

    Iodine Electrical Properties

    Iodine is Conductor of electricity. Refer to table below for the Electrical properties ofIodine

    Electrical Conductivity1e-7 S/m
    Resistivity10000000 m Ω
    Superconducting Point-

    Iodine Heat and Conduction Properties

    Thermal Conductivity0.449 W/(m K)
    Thermal Expansion-

    Iodine Magnetic Properties

    Magnetic TypeDiamagnetic
    Curie Point-
    Mass Magnetic Susceptibility-4.5e-9 m3/kg
    Molar Magnetic Susceptibility-1.14e-9 m3/mol
    Volume Magnetic Susceptibility-0.0000222

    Optical Properties of Iodine

    Refractive Index-

    Acoustic Properties of Iodine

    Speed of Sound-

    Iodine Thermal Properties - Enthalpies and thermodynamics

    Refer to table below for Thermal properties of Iodine

    Melting Point386.85 K (113.70°C, 236.66000000000008 °F)
    Boiling Point457.4 K (184.25°C, 363.65 °F)
    Critical Temperature819 K
    Superconducting Point-

    Enthalpies of Iodine

    Heat of Fusion7.76 kJ/mol
    Heat of Vaporization20.9 kJ/mol
    Heat of Combustion-

    Iodine Isotopes - Nuclear Properties of Iodine

    Iodine has 37 isotopes, with between 108 and 144 nucleons. Iodine has 1 stable naturally occuring isotopes.

    Isotopes of Iodine - Naturally occurring stable Isotopes: 127I.

    IsotopeZNIsotope Mass% AbundanceT halfDecay Mode
    108I5355108Synthetic
    109I5356109Synthetic
    110I5357110Synthetic
    111I5358111Synthetic
    112I5359112Synthetic
    113I5360113Synthetic
    114I5361114Synthetic
    115I5362115Synthetic
    116I5363116Synthetic
    117I5364117Synthetic
    118I5365118Synthetic
    119I5366119Synthetic
    120I5367120Synthetic
    121I5368121Synthetic
    122I5369122Synthetic
    123I5370123Synthetic
    124I5371124Synthetic
    125I5372125Synthetic
    126I5373126Synthetic
    127I5374127100%Stable
    128I5375128Synthetic
    129I5376129Synthetic
    130I5377130Synthetic
    131I5378131Synthetic
    132I5379132Synthetic
    133I5380133Synthetic
    134I5381134Synthetic
    135I5382135Synthetic
    136I5383136Synthetic
    137I5384137Synthetic
    138I5385138Synthetic
    139I5386139Synthetic
    140I5387140Synthetic
    141I5388141Synthetic
    142I5389142Synthetic
    143I5390143Synthetic
    144I5391144Synthetic