| Ordnungszahl: |
19 |
| Name: |
Potassium |
| Namensursprung: |
English: pot ash; symbol from Latin: kalium, (alkali). |
| Entdeckung: |
1807 by Sir Humphrey Davy in England |
| Beschreibung: |
Soft, waxy, silver-white metal. Eighth most abundant element in the earth's crust (20,900 ppm). Occurs only in compounds. |
| Vorkommen: |
Found in minerals like carnallite [(KMgCl3)·6H2O] and sylvite (potassium chloride, KCL). Pure metal is produced by the reaction of hot potassium chloride and sodium vapors in a special retort. |
| Verwendung: |
Used as potash in making glass and soap. Also as saltpeter, potassium nitrate (KNO3) to make explosives and to color fireworks in mauve. Formerly called kalium (K). Vital to function of nerve and muscle tissures. |
| Gruppe: |
Alkali Metal |
| Atomgewicht: |
39.0983 |
| Schmelzpunkt: |
63.25°C |
| Siedepunkt: |
759.9°C |
| Dichte bei 293 K: |
0.862 g/cm³ |
| Aggregatszustand bei Raumtemperatur: |
Solid |
| Schalen: |
2,8,8,1 |
| Orbitale: |
[Ar] 4s1 |
| Valenzen: |
1 |
| 1. Ionisierungs- potential: |
4.3407 V |
| 2. Ionisierungs- potential: |
31.625 V |
| 3. Ionisierungs- potential: |
45.72 V |
| Atomradius: |
2.77 Å |
| Spezifische Wärme: |
0.75 J/gK |
| Verdampfungswärme: |
79.870 kJ/mol |
| Schmelzwärme: |
2.334 kJ/mol |
| Thermischer Ausdehnungskoeffizient: |
82 10-6 K-1 |
| Röntgenemission Energie / Wellenlänge: |
| |
KA |
KB |
LA |
LB |
MA |
MB |
|
|
|
| eV |
3312.97 |
3589.72 |
0 |
0 |
0 |
0 |
|
|
|
| Å |
3.74242 |
3.4539 |
0 |
0 |
0 |
0 |
|
|
|
|
| Röntgenabsorption Energie / Wellenlänge: |
| |
K |
L-I |
L-II |
L-III |
M-I |
M-II |
M-III |
M-IV |
M-V |
| eV |
3608 |
0 |
294.6 |
0 |
0 |
0 |
0 |
0 |
0 |
| Å |
3.4364 |
0 |
42.086 |
0 |
0 |
0 |
0 |
0 |
0 |
|
| Röntgen Fluoreszenz Ausbeute: |
| |
KA |
KB |
LA |
LB |
MA |
MB |
|
|
|
| |
13.8% |
0% |
0% |
0% |
0% |
0% |
|
|
|
|
| Nuklide: |
| |
Anteil |
Gewicht |
Spin |
Halbwertszeit |
Zerfallsmodus |
| K39 |
93.22% |
38.9637 |
3/2 |
|
Stable |
| K40 |
0.118% |
39.974 |
4 |
1.28E09y |
β-,β+ |
| K41 |
6.77% |
40.9618 |
3/2 |
|
Stable |
| K42 |
0% |
41.963 |
2 |
12.36h |
β- |
| K43 |
0% |
43 |
3/2 |
22.3h |
β- |
|
