<Table> Chlorine, Cl <Tr> <Td_colspan="2"> </Td> </Tr> <Tr> <Th_colspan="2"> General properties </Th> </Tr> <Tr> <Th> Pronunciation </Th> <Td> / ˈklɔəriːn / or / ˈklɔərɪn / KLOHR - een or KLOHR - in </Td> </Tr> <Tr> <Th> Appearance </Th> <Td> pale yellow - green gas </Td> </Tr> <Tr> <Th> Standard atomic weight (A) </Th> <Td> (7001354460000000000 ♠ 35.446, 7001354570000000000 ♠ 35.457) conventional: 7001354500000000000 ♠ 35.45 </Td> </Tr> <Tr> <Th_colspan="2"> Chlorine 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> ↑ Cl ↓ Br </Td> </Tr> <Tr> <Td_colspan="2"> sulfur ← chlorine → argon </Td> </Tr> </Table> </Td> </Tr> </Table> </Td> </Tr> <Tr> <Th> Atomic number (Z) </Th> <Td> 17 </Td> </Tr> <Tr> <Th> Group, period </Th> <Td> group 17 (halogens), period 3 </Td> </Tr> <Tr> <Th> Block </Th> <Td> p - block </Td> </Tr> <Tr> <Th> Element category </Th> <Td> diatomic nonmetal </Td> </Tr> <Tr> <Th> Electron configuration </Th> <Td> (Ne) 3s 3p </Td> </Tr> <Tr> <Th> Electrons per shell </Th> <Td> 2, 8, 7 </Td> </Tr> <Tr> <Th_colspan="2"> Physical properties </Th> </Tr> <Tr> <Th> Phase (at STP) </Th> <Td> gas </Td> </Tr> <Tr> <Th> Melting point </Th> <Td> 171.6 K ​ (− 101.5 ° C, ​ − 150.7 ° F) </Td> </Tr> <Tr> <Th> Boiling point </Th> <Td> 239.11 K ​ (− 34.04 ° C, ​ − 29.27 ° F) </Td> </Tr> <Tr> <Th> Density (at STP) </Th> <Td> 3.2 g / L </Td> </Tr> <Tr> <Th> when liquid (at b.p.) </Th> <Td> 1.5625 g / cm </Td> </Tr> <Tr> <Th> Critical point </Th> <Td> 416.9 K, 7.991 MPa </Td> </Tr> <Tr> <Th> Heat of fusion </Th> <Td> (Cl) 6.406 kJ / mol </Td> </Tr> <Tr> <Th> Heat of vaporisation </Th> <Td> (Cl) 20.41 kJ / mol </Td> </Tr> <Tr> <Th> Molar heat capacity </Th> <Td> (Cl) 33.949 J / (mol K) </Td> </Tr> <Tr> <Td_colspan="2"> Vapour pressure <Table> <Tr> <Th> P (Pa) </Th> <Th> </Th> <Th> 10 </Th> <Th> 100 </Th> <Th> 1 k </Th> <Th> 10 k </Th> <Th> 100 k </Th> </Tr> <Tr> <Th> at T (K) </Th> <Td> 128 </Td> <Td> 139 </Td> <Td> 153 </Td> <Td> 170 </Td> <Td> 197 </Td> <Td> 239 </Td> </Tr> </Table> </Td> </Tr> <Tr> <Th_colspan="2"> Atomic properties </Th> </Tr> <Tr> <Th> Oxidation states </Th> <Td> 7, 6, 5, 4, 3, 2, 1, − 1 ​ (a strongly acidic oxide) </Td> </Tr> <Tr> <Th> Electronegativity </Th> <Td> Pauling scale: 3.16 </Td> </Tr> <Tr> <Th> Ionisation energies </Th> <Td> <Ul> <Li> 1st: 1251.2 kJ / mol </Li> <Li> 2nd: 2298 kJ / mol </Li> <Li> 3rd: 3822 kJ / mol </Li> <Li> (more) </Li> </Ul> </Td> </Tr> <Tr> <Th> Covalent radius </Th> <Td> 102 ± 4 pm </Td> </Tr> <Tr> <Th> Van der Waals radius </Th> <Td> 175 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> ​ orthorhombic </Td> </Tr> <Tr> <Th> Speed of sound </Th> <Td> 206 m / s (gas, at 0 ° C) </Td> </Tr> <Tr> <Th> Thermal conductivity </Th> <Td> 8.9 × 10 W / (m K) </Td> </Tr> <Tr> <Th> Electrical resistivity </Th> <Td>> 10 Ω m (at 20 ° C) </Td> </Tr> <Tr> <Th> Magnetic ordering </Th> <Td> diamagnetic </Td> </Tr> <Tr> <Th> Magnetic susceptibility </Th> <Td> − 40.5 10 cm / mol </Td> </Tr> <Tr> <Th> CAS Number </Th> <Td> 7782 - 50 - 5 </Td> </Tr> <Tr> <Th_colspan="2"> History </Th> </Tr> <Tr> <Th> Discovery and first isolation </Th> <Td> Carl Wilhelm Scheele (1774) </Td> </Tr> <Tr> <Th> Recognized as an element by </Th> <Td> Humphry Davy (1808) </Td> </Tr> <Tr> <Th_colspan="2"> Main isotopes of chlorine </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> Cl </Th> <Td> 76% </Td> <Td_colspan="3"> stable </Td> </Tr> <Tr> <Th> Cl </Th> <Td> trace </Td> <Td> 3.01 × 10 y </Td> <Td> β </Td> <Td> Ar </Td> </Tr> <Tr> <Td> ε </Td> <Td> </Td> </Tr> <Tr> <Th> Cl </Th> <Td> 24% </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> <Th_colspan="2"> General properties </Th> </Tr>

17 cl 35.453 what is the atomic number of this element