<Table> Potassium, K <Tr> <Td_colspan="2"> Potassium pearls (in paraffin oil, ~ 5 mm each) </Td> </Tr> <Tr> <Th_colspan="2"> General properties </Th> </Tr> <Tr> <Th> Pronunciation </Th> <Td> / poʊˈtæsiəm / po - TAS - ee - əm </Td> </Tr> <Tr> <Th> Appearance </Th> <Td> silvery gray </Td> </Tr> <Tr> <Th> Standard atomic weight (A) </Th> <Td> 7001390983000000000 ♠ 39.0983 (1) </Td> </Tr> <Tr> <Th_colspan="2"> Potassium in the periodic table </Th> </Tr> <Tr> <Td_colspan="2"> <Table> <Tr> <Td> <Table> <Tr> <Td> <Table> <Tr> <Td> Hydrogen </Td> <Td_colspan="30"> </Td> <Td> Helium </Td> </Tr> <Tr> <Td> Lithium </Td> <Td> Beryllium </Td> <Td_colspan="24"> </Td> <Td> Boron </Td> <Td> Carbon </Td> <Td> Nitrogen </Td> <Td> Oxygen </Td> <Td> Fluorine </Td> <Td> Neon </Td> </Tr> <Tr> <Td> Sodium </Td> <Td> Magnesium </Td> <Td_colspan="24"> </Td> <Td> Aluminium </Td> <Td> Silicon </Td> <Td> Phosphorus </Td> <Td> Sulfur </Td> <Td> Chlorine </Td> <Td> Argon </Td> </Tr> <Tr> <Td> Potassium </Td> <Td> Calcium </Td> <Td> Scandium </Td> <Td_colspan="14"> </Td> <Td> Titanium </Td> <Td> Vanadium </Td> <Td> Chromium </Td> <Td> Manganese </Td> <Td> Iron </Td> <Td> Cobalt </Td> <Td> Nickel </Td> <Td> Copper </Td> <Td> Zinc </Td> <Td> Gallium </Td> <Td> Germanium </Td> <Td> Arsenic </Td> <Td> Selenium </Td> <Td> Bromine </Td> <Td> Krypton </Td> </Tr> <Tr> <Td> Rubidium </Td> <Td> Strontium </Td> <Td> Yttrium </Td> <Td> </Td> <Td_colspan="13"> </Td> <Td> Zirconium </Td> <Td> Niobium </Td> <Td> Molybdenum </Td> <Td> Technetium </Td> <Td> Ruthenium </Td> <Td> Rhodium </Td> <Td> Palladium </Td> <Td> Silver </Td> <Td> Cadmium </Td> <Td> Indium </Td> <Td> Tin </Td> <Td> Antimony </Td> <Td> Tellurium </Td> <Td> Iodine </Td> <Td> Xenon </Td> </Tr> <Tr> <Td> Caesium </Td> <Td> Barium </Td> <Td> Lanthanum </Td> <Td> Cerium </Td> <Td> Praseodymium </Td> <Td> Neodymium </Td> <Td> Promethium </Td> <Td> Samarium </Td> <Td> Europium </Td> <Td> Gadolinium </Td> <Td> Terbium </Td> <Td> Dysprosium </Td> <Td> Holmium </Td> <Td> Erbium </Td> <Td> Thulium </Td> <Td> Ytterbium </Td> <Td> Lutetium </Td> <Td> Hafnium </Td> <Td> Tantalum </Td> <Td> Tungsten </Td> <Td> Rhenium </Td> <Td> Osmium </Td> <Td> Iridium </Td> <Td> Platinum </Td> <Td> Gold </Td> <Td> Mercury (element) </Td> <Td> Thallium </Td> <Td> Lead </Td> <Td> Bismuth </Td> <Td> Polonium </Td> <Td> Astatine </Td> <Td> Radon </Td> </Tr> <Tr> <Td> Francium </Td> <Td> Radium </Td> <Td> Actinium </Td> <Td> Thorium </Td> <Td> Protactinium </Td> <Td> Uranium </Td> <Td> Neptunium </Td> <Td> Plutonium </Td> <Td> Americium </Td> <Td> Curium </Td> <Td> Berkelium </Td> <Td> Californium </Td> <Td> Einsteinium </Td> <Td> Fermium </Td> <Td> Mendelevium </Td> <Td> Nobelium </Td> <Td> Lawrencium </Td> <Td> Rutherfordium </Td> <Td> Dubnium </Td> <Td> Seaborgium </Td> <Td> Bohrium </Td> <Td> Hassium </Td> <Td> Meitnerium </Td> <Td> Darmstadtium </Td> <Td> Roentgenium </Td> <Td> Copernicium </Td> <Td> Nihonium </Td> <Td> Flerovium </Td> <Td> Moscovium </Td> <Td> Livermorium </Td> <Td> Tennessine </Td> <Td> Oganesson </Td> </Tr> </Table> </Td> <Td> Na ↑ ↓ Rb </Td> </Tr> <Tr> <Td_colspan="2"> argon ← potassium → calcium </Td> </Tr> </Table> </Td> </Tr> </Table> </Td> </Tr> <Tr> <Th> Atomic number (Z) </Th> <Td> 19 </Td> </Tr> <Tr> <Th> Group, period </Th> <Td> group 1 (alkali metals), period 4 </Td> </Tr> <Tr> <Th> Block </Th> <Td> s - block </Td> </Tr> <Tr> <Th> Element category </Th> <Td> alkali metal </Td> </Tr> <Tr> <Th> Electron configuration </Th> <Td> (Ar) 4s </Td> </Tr> <Tr> <Th> Electrons per shell </Th> <Td> 2, 8, 8, 1 </Td> </Tr> <Tr> <Th_colspan="2"> Physical properties </Th> </Tr> <Tr> <Th> Phase (at STP) </Th> <Td> solid </Td> </Tr> <Tr> <Th> Melting point </Th> <Td> 336.7 K ​ (63.5 ° C, ​ 146.3 ° F) </Td> </Tr> <Tr> <Th> Boiling point </Th> <Td> 1032 K ​ (759 ° C, ​ 1398 ° F) </Td> </Tr> <Tr> <Th> Density (near r.t.) </Th> <Td> 0.862 g / cm </Td> </Tr> <Tr> <Th> when liquid (at m.p.) </Th> <Td> 0.828 g / cm </Td> </Tr> <Tr> <Th> Critical point </Th> <Td> 2223 K, 16 MPa </Td> </Tr> <Tr> <Th> Heat of fusion </Th> <Td> 2.33 kJ / mol </Td> </Tr> <Tr> <Th> Heat of vaporization </Th> <Td> 76.9 kJ / mol </Td> </Tr> <Tr> <Th> Molar heat capacity </Th> <Td> 29.6 J / (mol K) </Td> </Tr> <Tr> <Th_colspan="2"> Atomic properties </Th> </Tr> <Tr> <Th> Oxidation states </Th> <Td> + 1, − 1 ​ (a strongly basic oxide) </Td> </Tr> <Tr> <Th> Electronegativity </Th> <Td> Pauling scale: 0.82 </Td> </Tr> <Tr> <Th> Ionization energies </Th> <Td> <Ul> <Li> 1st: 418.8 kJ / mol </Li> <Li> 2nd: 3052 kJ / mol </Li> <Li> 3rd: 4420 kJ / mol </Li> <Li> (more) </Li> </Ul> </Td> </Tr> <Tr> <Th> Atomic radius </Th> <Td> empirical: 227 pm </Td> </Tr> <Tr> <Th> Covalent radius </Th> <Td> 203 ± 12 pm </Td> </Tr> <Tr> <Th> Van der Waals radius </Th> <Td> 275 pm </Td> </Tr> <Tr> <Td_colspan="2"> <Table> <Tr> <Td_colspan="2"> Spectral lines </Td> </Tr> </Table> </Td> </Tr> <Tr> <Th_colspan="2"> Miscellanea </Th> </Tr> <Tr> <Th> Crystal structure </Th> <Td> ​ body - centered cubic (bcc) </Td> </Tr> <Tr> <Th> Speed of sound thin rod </Th> <Td> 2000 m / s (at 20 ° C) </Td> </Tr> <Tr> <Th> Thermal expansion </Th> <Td> 83.3 μm / (m K) (at 25 ° C) </Td> </Tr> <Tr> <Th> Thermal conductivity </Th> <Td> 102.5 W / (m K) </Td> </Tr> <Tr> <Th> Electrical resistivity </Th> <Td> 72 nΩ m (at 20 ° C) </Td> </Tr> <Tr> <Th> Magnetic ordering </Th> <Td> paramagnetic </Td> </Tr> <Tr> <Th> Magnetic susceptibility </Th> <Td> + 20.8 10 cm / mol (298 K) </Td> </Tr> <Tr> <Th> Young's modulus </Th> <Td> 3.53 GPa </Td> </Tr> <Tr> <Th> Shear modulus </Th> <Td> 1.3 GPa </Td> </Tr> <Tr> <Th> Bulk modulus </Th> <Td> 3.1 GPa </Td> </Tr> <Tr> <Th> Mohs hardness </Th> <Td> 0.4 </Td> </Tr> <Tr> <Th> Brinell hardness </Th> <Td> 0.363 MPa </Td> </Tr> <Tr> <Th> CAS Number </Th> <Td> 7440 - 09 - 7 </Td> </Tr> <Tr> <Th_colspan="2"> History </Th> </Tr> <Tr> <Th> Discovery and first isolation </Th> <Td> Humphry Davy (1807) </Td> </Tr> <Tr> <Th_colspan="2"> Main isotopes of potassium </Th> </Tr> <Tr> <Td_colspan="2"> <Table> <Tr> <Th> Isotope </Th> <Th> Abundance </Th> <Th> Half - life (t) </Th> <Th> Decay mode </Th> <Th> Product </Th> </Tr> <Tr> <Th> </Th> <Td> 93.258% </Td> <Td_colspan="3"> stable </Td> </Tr> <Tr> <Th> </Th> <Td> 0.012% </Td> <Td> 1.248 × 10 y </Td> <Td> β </Td> <Td> Ca </Td> </Tr> <Tr> <Td> ε </Td> <Td> Ar </Td> </Tr> <Tr> <Td> β </Td> <Td> Ar </Td> </Tr> <Tr> <Th> </Th> <Td> 6.730% </Td> <Td_colspan="3"> stable </Td> </Tr> </Table> </Td> </Tr> <Tr> <Td_colspan="2"> <Ul> <Li> view </Li> <Li> talk </Li> <Li> </Li> </Ul> references in Wikidata </Td> </Tr> </Table> <Tr> <Td_colspan="2"> Potassium pearls (in paraffin oil, ~ 5 mm each) </Td> </Tr>

Where is potassium found in the periodic table
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