Frae Wikipedia, the free beuk o knawledge
Potassium, 19K Potassium pearls (in paraffin ile, ~5 mm ilk) |
| Potassium |
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| Pronunciation | (pə-TASS-ee-əm) |
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| Appearance | sillery gray |
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| Standard atomic weight Ar, std(K) | 7001390983000000000♠39.0983(1)[1] |
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| Potassium in the periodic cairt |
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|
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| Atomic nummer (Z) | 19 |
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| Group | group 1 (alkali metals) |
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| Period | period 4 |
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| Block | s-block |
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| Element category | Alkali metal |
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| Electron confeeguration | [Ar] 4s1 |
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| Electrons per shell | 2, 8, 8, 1 |
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| Pheesical properties |
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| Phase at STP | solit |
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| Meltin pynt | 336.7 K (63.5 °C, 146.3 °F) |
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| Bylin pynt | 1032 K (759 °C, 1398 °F) |
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| Density (near r.t.) | 0.862 g/cm3 |
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| when liquid (at m.p.) | 0.828 g/cm3 |
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| Creetical pynt | 2223 K, 16[2] MPa |
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| Heat o fusion | 2.33 kJ/mol |
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| Heat o vapourisation | 76.9 kJ/mol |
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| Molar heat capacity | 29.6 J/(mol·K) |
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| Atomic properties |
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| Oxidation states | −1, +1 strangly basic |
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| Electronegativity | Pauling scale: 0.82 |
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| Ionisation energies | |
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| Atomic radius | empirical: 227 pm |
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| Covalent radius | 203±12 pm |
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| Van der Waals radius | 275 pm |
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 Colour lines in a spectral rangeSpectral lines o potassium |
| Ither properties |
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| Naitural occurrence | primordial |
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| Creestal structur | body-centred cubic (bcc) |
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| Speed o soond thin rod | 2000 m/s (at 20 °C) |
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| Thermal expansion | 83.3 µm/(m·K) (at 25 °C) |
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| Thermal conductivity | 102.5 W/(m·K) |
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| Electrical resistivity | 72 n Ω·m (at 20 °C) |
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| Magnetic orderin | paramagnetic[3] |
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| Young's modulus | 3.53 GPa |
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| Shear modulus | 1.3 GPa |
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| Bulk modulus | 3.1 GPa |
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| Mohs haurdness | 0.4 |
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| Brinell haurdness | 0.363 MPa |
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| CAS Nummer | 7440-09-7 |
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| History |
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| Diskivery | Humphry Davy (1807) |
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| First isolation | Humphry Davy (1807) |
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| Main isotopes o potassium |
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| | references |
| style="text-align:left"|
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|
|
in
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calc from C
|
diff
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report
|
ref
|
| C
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63.5
|
—
|
—
|
|
|
| K
|
336.7
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336.6
|
0.1
|
delta
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|
| F
|
146.3
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146.3
|
0
|
|
|
| WD
|
336.7 !336.7 kelvin 63.65 Celsius 
|
|
|
|
| input
|
C: 63.5, K: 336.7, F: 146.3
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| comment
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|
| style="text-align:left"|
|
|
|
in
|
calc from C
|
diff
|
report
|
ref
|
| C
|
759
|
—
|
—
|
|
|
| K
|
1032
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1032
|
0
|
|
|
| F
|
1398
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1398
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0
|
|
|
| WD
|
1047 !1047 kelvin 773.85 Celsius
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|
|
|
| input
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C: 759, K: 1032, F: 1398
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| comment
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|
References
Thir references will appear in the airticle, but this list appears anerly on this page.
- ↑ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
- ↑ Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nt ed.). CRC Press. p. 4.122. ISBN 1439855110.
- ↑ Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
