I - Iodine

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.

The table below shows the abundance of Iodine in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.

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)

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

The positions of the atoms inside the unit cell are described by the set of atomic positions ( x_i, y_i, z_i) 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 Name	Cmca
Space Group Number	64
Crystal Structure	Base Centered Orthorhombic
Number of atoms per unit cell	2

Iodine atoms have 53 electrons and the electronic shell structure is [2, 8, 18, 18, 7] with Atomic Term Symbol (Quantum Numbers) ²P_3/2.

Atomic Number	53
Number of Electrons (with no charge)	53
Number of Protons	53
Mass Number	127
Number of Neutrons	74
Shell structure (Electrons per energy level)	2, 8, 18, 18, 7
Electron Configuration	[Kr] 4d10 5s2 5p5
Valence Electrons	5s2 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

n		s	p	d	f

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.

Atomic Structure of Iodine

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

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

Absorption spectrum of Iodine

The electron affinity of Iodine is 295.2 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

Refer to below table for Iodine Physical Properties

Elastic Properties

Hardness of Iodine - Tests to Measure of Hardness of Element

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

Iodine Heat and Conduction Properties

Iodine Magnetic Properties

Optical Properties of Iodine

Acoustic Properties of Iodine

Refer to table below for Thermal properties of Iodine

Enthalpies 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.

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.

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.

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