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Symbol:CI
17 atomic, 35.45 atomic mass
35mass
17p,17e,18n
Period 3
valance electron:

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Halogen family
Group:17
relative element:
fluorine (F),
bromine (Br),
iodine (I),
astatine (At),

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Strength and weakness about chlorine

Chlorination is used extensively by municipal water treatment plants to disinfect water.

Chlorination kills many pathogenic bacteria (including those which cause typhoid, cholera and dysentery)

It is ironic that chlorination, the very process by which we cleanse our water of infectious organisms, can create cancer causing substances from otherwise innocent chemicals in water.

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“Uses, Benefits, and Safety of Chlorine | Chemical Safety Facts.” ChemicalSafetyFacts.org, Chemicalsafetyfacts.org, 21 Aug. 2018, www.chemicalsafetyfacts.org/chlorine/.

www.chemicalsafetyfacts.org/chlorine/

“Dangers of Chlorine? - Ask Dr. Weil.” DrWeil.com, 4 Dec. 2016, www.drweil.com/health-wellness/balanced-living/healthy-living/dangers-of-chlorine/.

www.drweil.com/health-wellness/balanced-living/healthy-living/dangers-of-chlorine/

“Chemistry.” Properties Halogen Elements And List, byjus.com/chemistry/occurrence-of-halogen-group/.

Gutmann, Viktor, et al. “Halogen Element.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 3 Nov. 2017, www.britannica.com/science/halogen-element.

“Chlorine Facts.” Math, www.softschools.com/facts/periodic_table/chlorine_facts/194/.

Clairemaust. “Claire's Chlorine Quest.” Claires Chlorine Quest, 13 Oct. 2018, claireschlorinequest.wordpress.com/tag/pros-and-cons-of-chlorine/.

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Chlorine (Cl) is a member of the halogen group with an atomic number of seventeen. One of its forms, NaCl, has been in use since ancient times.

Chlorine has been in use for thousands of years in other forms, but it wasn't named until 1810 by Sir Humphry Davy.
Only fluorine is a lighter halogen than chlorine.
It is the second most common halogen on Earth.
The element itself is the 21st most common element, at about 170 parts per million.
It took almost 200 years from the discovery of chlorine gas for it to become recognized as an element.

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The problem about drinking water

The purpose is try to tell us how it solve the water problem

Chlorination is used extensively by municipal water treatment plants to disinfect water. However, the gaseous chlorine used by these plants is much too dangerous for home use. Household bleach (a 5.25% solution of sodium hypochlorite which is equivalent to 5% available chlorine) can be used for disinfecting drinking water. It is related to environment