I - Iodine

53
I
Iodine

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

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. You can also download Printable Periodic Table of Elements Flashcards for Iodine in a PDF format.

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
Natural OccurancePrimordial
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
269
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').

Discovered By B. Courtois
Discovery Date 1811 in France
First Isolation 1811
Isolated by B. Courtois

Courtois discovered it in the ashes of seaweed.

Iodine Uses

Iodine salts are used in photographic film and as an antiseptic for wounds. The radioactive isotope iodine-131 is used to treat thyroid cancer. It is often added in small quantity to table salt in order to avoid iodine deficiency.

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
Space Group Number64
Crystal StructureBase Centered Orthorhombic
Number of atoms per unit cell2
53 I Iodine - Crystal Structure | SchoolMyKids

The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic are 1,4,2 respectively.

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
nspdf

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 Calculated115 pm(1.15 Å)
Atomic Radius Empirical140 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

Spectral Lines of Iodine - Atomic Spectrum of Iodine

A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.

Spectral lines are the result of interaction between a quantum system and a single photon. A spectral line may be observed either as an emission line or an absorption line.

Spectral lines are highly atom-specific, and can be used to identify the chemical composition of any medium. Several elements, including helium, thallium, and caesium, were discovered by spectroscopic means. They are widely used to determine the physical conditions of stars and other celestial bodies that cannot be analyzed by other means.

Emission spectrum of Iodine

Emission Spectrum of Iodine | SchoolMyKids

Absorption spectrum of Iodine

Absorption 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

Ionization energy is the amount of energy required to remove an electron from an atom or molecule.in chemistry, this energy is expresed in kilocalories per mole (kcal/mol) or kilojoules per mole (kJ/mol).

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

Electrical resistivity measures element's electrical resistance or how strongly it resists electric current.The SI unit of electrical resistivity is the ohm-metre (Ω⋅m). While Electrical conductivity is the reciprocal of electrical resistivity. It represents a element's ability to conduct electric current. The SI unit of electrical conductivity is siemens per metre (S/m).

Iodine is a Insulator. Refer to table below for the Electrical properties of Iodine

Electrical conductors Insulator
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, 236.660 °F)
Boiling Point457.4 K(184.25 °C, 363.650 °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

Regulatory and Health - Health and Safety Parameters and Guidelines

The United States Department of Transportation (DOT) identifies hazard class of all dangerous elements/goods/commodities either by its class (or division) number or name. The DOT has divided these materials into nine different categories, known as Hazard Classes.

Corrosive substances

NFPA 704 is a Standard System for the Identification of the Hazards of Materials for Emergency Response. NFPA is a standard maintained by the US based National Fire Protection Association.

The health (blue), flammability (red), and reactivity (yellow) rating all use a numbering scale ranging from 0 to 4. A value of zero means that the element poses no hazard; a rating of four indicates extreme danger.

NFPA Fire Rating0Will not burn
NFPA Health Rating3 Flash Points below 37.8°C (100°F)
NFPA Reactivity Rating0 Will not burn
NFPA Hazards
Autoignition Point-
Flashpoint-

Database Search

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

DatabaseIdentifier number
CAS Number - Chemical Abstracts Service (CAS)CAS7553-56-2
RTECS NumberRTECSNN1575000
CID Number CID807
Gmelin Number-
NSC Number-

Frequently Asked Questions (FAQ)

Find the answers to the most frequently asked questions about Iodine

The electronic configuration of Iodine is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p5.

The abbreviated electronic configuration of Iodine is [Kr] 4d10 5s2 5p5. To form abbreviated notation of electronic configuration, the completely filled subshells are replaced by the noble gas of the preceding period in square brackets.

Symbol of Iodine is I. Iodine is a chemical element with symbol I and atomic number 53.

Iodine is a chemical element with the symbol I and atomic number 53. Iodine is the 53 element on the periodic table. It is located in group 17 and period 5 in the modern periodic table.

The atomic number of Iodine is 53.

Iodine is of SlateGray color.

The element Iodine was discovered by B. Courtois in year 1811 in France. Iodine was first isolated by B. Courtois in 1811.

Iodine has 7 valence electrons. Iodine has 53 electrons out of which 7 valence electrons are present in the 5s2 5p5 outer orbitals of atom.

Melting Point of Iodine is 386.85 K.

Boiling Point of Iodine is 457.4 K.

Melting Point of Iodine in Kelvin is 386.85 K.

Boiling Point of Iodine in Kelvin is 457.4 K.

Melting Point of Iodine in Celsius is 113.70 °C.

Boiling Point of Iodine in Celsius is 184.25 °C.

Melting Point of Iodine in Fahrenheit is 236.66 °F.

Boiling Point of Iodine in Fahrenheit is 363.65 °F.

The electronic configuration of Iodine will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p5.

The electronic configuration of Iodine will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p5.