Symbol	Ta
Atomnummer	73
Gruppe	5 (Vanadiumgruppe)
Periode	6
Blok	d
Klassifikation	Overgangsmetal

Udseende	Gray blue
Farve	Grå

Antal protoner	73 p+
Antal neutroner	108 n0
Antal elektroner	73 e-

Fra Wikipedia, den gratis encyklopædiTantal (efter Tantalos fra den græske mytologi) er det 73. grundstof i det periodiske system, og har det kemiske symbol Ta: Under normale tryk- og temperaturforhold optræder dette overgangsmetal som et mørkt, hårdt og korrosionsbestandigt metal. Selvom tantal er hårdt, er det samtidig formbart. Det er en fremragende elektrisk leder og varmeleder, og dertil er det særdeles varmebestandigt; smeltepunktet på 3017° C overgåes kun af wolfram, rhenium og kulstof. Tantal er berømt for sin modstandsdygtighed overfor korrosion: Ved temperaturer under 150 grader Celsius angribes tantal ikke engang af det ellers meget agressive kongevand. Til gengæld kan kaliumhydroxid, flussyre samt sure opløsninger med svovltrioxid og fluor-ioner angribe metallet.

Fase ved STP	Fast
Massefylde	16.69 g/cm3
Atommasse	180.948 u

Smeltepunkt	3290 K 3016.85 °C 5462.33 °F
Kogepunkt	5731 K 5457.85 °C 9856.13 °F
Fordampningsvarme	737 kJ/mol

Elektronegativitet (Pauling Scale)	1.5
Elektronaffinitet	31 kJ/mol
Oxidationstrin	−3, −1, 0, +1, +2, +3, +4, +5 (a mildly acidic oxide)
Ioniseringsenergier	761 kJ/mol 1500 kJ/mol

Elektronkonfiguration Kortfattet konfiguration	[Xe] 4f14 5d3 6s2
Elektronkonfiguration Fuld konfiguration	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d3 6s2
Elektronkonfigurationsdiagram	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d3 6s2
Elektroner pr. Skal	2, 8, 18, 32, 11, 2
Valenselektroner	2
Valency-elektroner	5
Bohrs atommodel	Figur: Skaldiagram af Tantal (Ta) atom.
Orbital diagram 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 6s

Opdaget	Anders Gustaf Ekeberg (1802)
Recognized as a distinct element by	Heinrich Rose (1844)
Opdagelse af tantal Tantalum was discovered in Sweden in 1802 by Anders Ekeberg, in two mineral samples – one from Sweden and the other from Finland. One year earlier, Charles Hatchett had discovered columbium (now niobium), and in 1809 the English chemist William Hyde Wollaston compared its oxide, columbite with a density of 5.918 g/cm3, to that of tantalum, tantalite with a density of 7.935 g/cm3. He concluded that the two oxides, despite their difference in measured density, were identical and kept the name tantalum. After Friedrich Wöhler confirmed these results, it was thought that columbium and tantalum were the same element. This conclusion was disputed in 1846 by the German chemist Heinrich Rose, who argued that there were two additional elements in the tantalite sample, and he named them after the children of Tantalus: niobium (from Niobe, the goddess of tears), and pelopium (from Pelops). The supposed element "pelopium" was later identified as a mixture of tantalum and niobium, and it was found that the niobium was identical to the columbium already discovered in 1801 by Hatchett.

CAS Number	7440-25-7
ChemSpider ID	22395
EC number	231-135-5
PubChem CID Number	23956