How to denote 5 chlorine atoms
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Answer:
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the Pauling scale, behind only oxygen and fluorine.
Chlorine, 17Cl
A glass container filled with chlorine gas
Chlorine
Pronunciation
/ˈklɔːriːn, -aɪn/ (KLOH-reen, -ryn)
Appearance
pale yellow-green gas
Standard atomic weight Ar, std(Cl)
[35.446, 35.457] conventional: 35.45
Chlorine in the periodic table
Hydrogen
Helium
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
Sodium
Magnesium
Aluminium
Silicon
Phosphorus
Sulfur
Chlorine
Argon
Potassium
Calcium
Scandium
Titanium
Vanadium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
Bromine
Krypton
Rubidium
Strontium
Yttrium
Zirconium
Niobium
Molybdenum
Technetium
Ruthenium
Rhodium
Palladium
Silver
Cadmium
Indium
Tin
Antimony
Tellurium
Iodine
Xenon
Caesium
Barium
Lanthanum
Cerium
Praseodymium
Neodymium
Promethium
Samarium
Europium
Gadolinium
Terbium
Dysprosium
Holmium
Erbium
Thulium
Ytterbium
Lutetium
Hafnium
Tantalum
Tungsten
Rhenium
Osmium
Iridium
Platinum
Gold
Mercury (element)
Thallium
Lead
Bismuth
Polonium
Astatine
Radon
Francium
Radium
Actinium
Thorium
Protactinium
Uranium
Neptunium
Plutonium
Americium
Curium
Berkelium
Californium
Einsteinium
Fermium
Mendelevium
Nobelium
Lawrencium
Rutherfordium
Dubnium
Seaborgium
Bohrium
Hassium
Meitnerium
Darmstadtium
Roentgenium
Copernicium
Nihonium
Flerovium
Moscovium
Livermorium
Tennessine
Oganesson
F
↑
Cl
↓
Br
sulfur ← chlorine → argon
Atomic number (Z)
17
Group
group 17 (halogens)
Period
period 3
Block
p-block
Element category
Reactive nonmetal
Electron configuration
[Ne] 3s2 3p5
Electrons per shell
2, 8, 7
Physical properties
Phase at STP
gas
Melting point
(Cl2) 171.6 K (−101.5 °C, −150.7 °F)
Boiling point
(Cl2) 239.11 K (−34.04 °C, −29.27 °F)
Density (at STP)
3.2 g/L
when liquid (at b.p.)
1.5625 g/cm3[1]
Critical point
416.9 K, 7.991 MPa
Heat of fusion
(Cl2) 6.406 kJ/mol
Heat of vaporisation
(Cl2) 20.41 kJ/mol
Molar heat capacity
(Cl2)
33.949 J/(mol·K)
Vapour pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 128 139 153 170 197 239
Atomic properties
Oxidation states
−1, +1, +2, +3, +4, +5, +6, +7 (a strongly acidic oxide)
Electronegativity
Pauling scale: 3.16
Ionisation energies
1st: 1251.2 kJ/mol
2nd: 2298 kJ/mol
3rd: 3822 kJ/mol
(more)
Covalent radius
102±4 pm
Van der Waals radius
175 pm
Color lines in a spectral r
The most common compound of chlorine, sodium chloride (common salt), has been known since ancient times. Around 1630, chlorine gas was first synthesised in a chemical reaction, but not recognised as a fundamentally important substance. Carl Wilhelm Scheele wrote a description of chlorine gas in 1774, supposing it to be an oxide of a new element. In 1809, chemists suggested that the gas might be a pure element, and this was confirmed by Sir Humphry Davy in 1810, who named it from Ancient Greek: χλωρός, romanized: khlôros, lit. 'pale green' based on its colour.
Because of its great reactivity, all chlorine in the Earth's crust is in the form of ionic chloride compounds, which includes table salt. It is the second-most abundant halogen (after fluorine) and twenty-first most abundant chemical element in Earth's crust. These crustal deposits are nevertheless dwarfed by the huge reserves of chloride in seawater.
Elemental chlorine is commercially produced from brine by electrolysis, predominantly in the chlor-alkali process. The high oxidising potential of elemental chlorine led to the development of commercial bleaches and disinfectants, and a reagent for many processes in the chemical industry. Chlorine is used in the manufacture of a wide range of consumer products, about two-thirds of them organic chemicals such as polyvinyl chloride (PVC), many intermediates for the production of plastics, and other end products which do not contain the element. As a common disinfectant, elemental chlorine and chlorine-generating compounds are used more directly in swimming pools to keep them sanitary. Elemental chlorine at high concentration is extremely dangerous, and poisonous to most living organisms. As a chemical warfare agent, chlorine was first used in World War I as a poison gas weapon.
In the form of chloride ions, chlorine is necessary to all known species of life. Other types of chlorine compounds are rare in living organisms, and artificially produced chlorinated organics range from inert to toxic. In the upper atmosphere, chlorine-containing organic molecules such as chlorofluorocarbons have been implicated in ozone depletion. Small quantities of elemental chlorine are generated by oxidation of chloride to hypochlorite in neutrophils as part of an immune system response against bacteria.