Jern

Symbol	Fe
Atomnummer	26
Gruppe	8 (Jerngruppe)
Periode	4
Blok	d
Klassifikation	Overgangsmetal

Udseende	Lustrous metallic with a grayish tinge
Farve	Grå

Antal protoner	26 p+
Antal neutroner	30 n0
Antal elektroner	26 e-

Fra Wikipedia, den gratis encyklopædiJern (oldnordisk: iarn, germansk: isarn) er navnet på et tungmetal, et grundstof i det periodiske system med kemisk symbol Fe (latin Ferrum, Jern) og atomnummer 26. Det er et metal og står i 4. periode og i 8. undergruppe, da der i det periodiske system både er hovedgrupper og undergrupper, og jern(Fe) står i undergruppen. Jern er det tiende mest almindelige grundstof i universet og udgør 6,2 % af jordens overflade. Det er dermed det fjerde mest udbredte grundstof på Jorden (efter oxygen, silicium og aluminium). Jern menes at være hovedbestanddelen af Jordens kerne.

Fase ved STP	Fast
Massefylde	7.874 g/cm3
Atommasse	55.8452 u

Smeltepunkt	1811 K 1537.85 °C 2800.13 °F
Kogepunkt	3134 K 2860.85 °C 5181.53 °F
Fordampningsvarme	349.5 kJ/mol

Elektronegativitet (Pauling Scale)	1.83
Elektronaffinitet	14.785 kJ/mol
Oxidationstrin	−4, −2, −1, 0, +1, +2, +3, +4, +5, +6, +7 (an amphoteric oxide)
Ioniseringsenergier	762.5 kJ/mol 1561.9 kJ/mol 2957 kJ/mol 5290 kJ/mol 7240 kJ/mol 9560 kJ/mol 12060 kJ/mol 14580 kJ/mol 22540 kJ/mol 25290 kJ/mol 28000 kJ/mol 31920 kJ/mol 34830 kJ/mol 37840 kJ/mol 44100 kJ/mol 47206 kJ/mol 122200 kJ/mol 131000 kJ/mol 140500 kJ/mol 152600 kJ/mol 163000 kJ/mol 173600 kJ/mol 188100 kJ/mol 195200 kJ/mol 851800 kJ/mol 895161 kJ/mol

Elektronkonfiguration Kortfattet konfiguration	[Ar] 3d6 4s2
Elektronkonfiguration Fuld konfiguration	1s2 2s2 2p6 3s2 3p6 3d6 4s2
Elektronkonfigurationsdiagram	1s2 2s2 2p6 3s2 3p6 3d6 4s2
Elektroner pr. Skal	2, 8, 14, 2
Outer shell electrons	2
Valence electrons (incl. d)	8
Valency-elektroner	2, 3
Bohrs atommodel	Figur: Skaldiagram af Jern (Fe) atom.
Orbital diagram	1s 2s 2p 3s 3p 3d 4s

Opdaget

Middle East (5000 fvt.)

Opdagelse af jern There is evidence that iron was known from before 5000 BC. The oldest known iron objects used by humans are some beads of meteoric iron, made in Egypt in about 4000 BC. The discovery of smelting around 3000 BC led to the start of the Iron Age around 1200 BC and the prominent use of iron for tools and weapons. However, iron artefacts of great age are much rarer than objects made of gold or silver due to the ease with which iron corrodes. The technology developed slowly, and even after the discovery of smelting it took many centuries for iron to replace bronze as the metal of choice for tools and weapons.

Original word	iren
Language of origin	Anglo-Saxon
Name source	Egenskaber
Meaning	“Iren”
Symbol origin	The element symbol, Fe, was shortened from the Latin word 'ferrum' meaning 'firmness'.
Naming The name derives from the Anglo-Saxon word 'iren'. The element has been known from prehistoric times.

CAS Number	7439-89-6
ChemSpider ID	22368
EC number	231-096-4
PubChem CID Number	23925