Symbol	I
Atomnummer	53
Gruppe	17 (Halogener)
Periode	5
Blok	p
Klassifikation	Ikkemetal

Udseende	Lustrous metallic gray, violet as a gas
Farve	Skifergrå

Antal protoner	53 p+
Antal neutroner	74 n0
Antal elektroner	53 e-

Fra Wikipedia, den gratis encyklopædiJod (også kaldet iod) (af græsk "io-eides" betydende "viol-farve") er et grundstof med atomnummer 53 i det periodiske system. Symbol I. Jod tilhører 7. hovedgruppe (halogenerne). Jod er det tungeste grundstof der er nødvendigt for mennesker og mange andre levende organismer. Stoffet indgår i de vigtige skjoldbruskkirtelhormoner. Mangel på jod kan føre til lavere stofskifte, og er den primære årsag til sygdommene struma og kretinisme (en særlig form for dværgvækst og reduceret psykisk udvikling).

Fase ved STP	Fast
Massefylde	4.933 g/cm3
Atommasse	126.904 u

Smeltepunkt	386.85 K 113.7 °C 236.66 °F
Kogepunkt	457.4 K 184.25 °C 363.65 °F
Fordampningsvarme	20.9 kJ/mol

Elektronegativitet (Pauling Scale)	2.66
Elektronaffinitet	295.153 kJ/mol
Oxidationstrin	−1, +1, +3, +4, +5, +6, +7 (a strongly acidic oxide)
Ioniseringsenergier	1008.4 kJ/mol 1845.9 kJ/mol 3180 kJ/mol

Elektronkonfiguration Kortfattet konfiguration	[Kr] 4d10 5s2 5p5
Elektronkonfiguration Fuld konfiguration	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p5
Elektronkonfigurationsdiagram	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p5
Elektroner pr. Skal	2, 8, 18, 18, 7
Valenselektroner	7
Valency-elektroner	1,3,5,7
Bohrs atommodel	Figur: Skaldiagram af Jod (I) atom.
Orbital diagram	1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p

Opdagelse og første isolation	Bernard Courtois (1811)
Navngivet af	Joseph Louis Gay-Lussac (1813)
Opdagelse af jod In 1811, iodine was discovered by French chemist Bernard Courtois. He once added excessive sulfuric acid when making Saltpetre and a cloud of purple vapour rose. He noted that the vapour crystallised on cold surfaces, making dark crystals. Courtois suspected that this material was a new element but lacked funding to pursue it further. Courtois gave samples to his friends, Charles Bernard Desormes and Nicolas Clément, to continue research. He also gave some of the substance to chemist Joseph Louis Gay-Lussac, and to physicist André-Marie Ampère. On 29 November 1813, Desormes and Clément made Courtois' discovery public. They described the substance to a meeting of the Imperial Institute of France. On 6 December, Gay-Lussac announced that the new substance was either an element or a compound of oxygen. Gay-Lussac suggested the name "iode", from the Ancient Greek ἰοειδής (ioeidēs, "violet"), because of the colour of iodine vapor. Ampère had given some of his sample to English chemist Humphry Davy, who experimented on the substance and noted its similarity to chlorine. Davy sent a letter dated 10 December to the Royal Society of London stating that he had identified a new element. Arguments erupted between Davy and Gay-Lussac over who identified iodine first, but both scientists acknowledged Courtois as the first to isolate the element.

CAS Number	7553-56-2
ChemSpider ID	4514549
EC number	231-442-4
PubChem CID Number	807