HALOGENS
Group 17
GENERAL INFORMATION
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Halogen comes from Greek terms halo ("salt") and gen
("origin"), indicating the role of the elements in the formation of
chemical salts.
Only one halogen occurs naturally as an element Astatine.
They are common and abundant in chemical compounds
The halogens are mostly diatomic (astatine isn’t because of a
lack of knowledge)
Binary compounds of the halogens are called halides.
When one of the elements becomes part of a compound, the
ending for its name is changed from -ine to -ide; e.g., chlorine
→ chloride.
AT
Fluorine Facts
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Atomic number 9
Atomic Weight 18.9984 amu
Diatomic molecule
Pale, yellow, corrosive gas at room temperature
Most reactive element
Yellow when in a liquid form
Melting Point: -219.62°C
Boiling Point: -188°C
Density 1.696 g/L
Most electronegative element
Lightest halogen
Irritating odor
Only one stable isotope. Fluorine-19
Comes from latin word ‘’fluorum’’ meaning to flow
Fluorine Discovery and Uses
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In 1771 Carl Wilhelm Scheele got hydrofluoric acid in an impure state.
He heated fluorspar with concentrated sulfuric acid
The nearly anhydrous acid was prepared in 1809
it was then suggested that it was a compound of hydrogen with an
unknown element similar to chlorine, which is when the name fluorine was
suggested
In 1886 Henri Moissan was the first person to ever isolate fluorine and he
won a Nobel Prize for Chemistry
.065% of earth’s crust
Found in nature only in the form of its chemical compounds
Component in animal bones and teeth
Chlorine Facts
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Second lightest member of the halogen family
Toxic, corrosive, greenish-yellow gas at room temperature
Can irritate the eyes and respiratory system
Becomes a liquid at -34 degrees Celsius
High electronegativity
Atomic number of 17
Atomic mass of 35.453
Density: 3.21 x 10^-3 g/cm^3
Boiling point: -34.04°C
Melting point: -101.5°C
Soluble in water
Diatomic element
Chlorine Uses and Discovery
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Carl Wilhelm Scheele treated powdered black oxide of manganese with
hydrochloric acid and obtained a greenish-yellowish gas, now known as
chlorine
It was officially recognized as an element in 1810 by Humphry Davy who
gave it an official name
From the Greek word “chloros” meaning yellowish-green.
Usually found only in compounds in nature or in very small amounts of
volcanic gases
Makes up .017% of the earth’s crust
First gas used in chemical warfare in world war I
Used in water purification
Used in pools
Bromine
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Atomic Number 35
Atomic Weight 79.909
Diatomic molecule
deep red liquid changes easily to vapor at room temperature\
only nonmetallic element liquid at room temperature
horrible odor- bromos- Greek for stench
melting point: 19.4°F (-7.2°C) and boiling point: 137.84°F (58.8°C)
density: 3.11 grams per cubic centimeters
two stable isotopes: Bromine-79 and Bromine-81
Bromine Discovery and Uses
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discovered in 1825 by Carl Löwig and Antoine-Jérôme Balard by passing chlorine
through salt water and in salt marshes
found earlier in Mediterranean mollusks to make “royal dye”
Bromine is a hazardous material causing severe burns and irritations when it comes
in contact with the skin or eyes
used in the manufacture of ethylene dibromide which is a chemical added to leaded
gasoline to keep the lead from accumulating in the engine
silver bromide is used in photography is the largest use of bromine
it can also be used in pools as a water purifier/ disinfectant
used in agriculture to prevent pests
Iodine Facts
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Atomic Number 53
Atomic Weight 126.9045
Diatomic molecule
One stable isotope: iodine-127, about 30 artificial isotopes
Heaviest Halogen
Solid @ room temperature heavy grayish black, metallic looking substance
Usually sublimes into purple vapor
Iodine vapor has a violet color and harsh odor
iodes- means violet in Greek
can melt under the right conditions: at 236.3°F (113.5°C)
boils at 363°F (184°C)
density:4.98 grams per cubic centimeter (five times that of water)
concentrated in Earth’s crust where oceans used to be
Iodine Discovery and Uses
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Bernard Courtois (1777-1838) discovered Iodide in 1811 when he added too much
sulfuric acid to seaweed ashes creating a purple solution
Hormone thyroxine contains iodine controls body’s rate of mental and physical
development
Goiter (the enlargement of the thyroid) is cured by taking Iodide tablets
Iodine-131 a radioactive isotopes found to treat thyroid cancer
Iodine-125 is effective in treating a rare form of eye cancer
Used in antiseptics and drugs it is also a catalyst
kills bacteria and other disease-forming organisms
too much can burn or irritate the skin
Astatine
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semi metallic element
produced by the radioactive decay of uranium and thorium
the heaviest member of the group with an atomic mass of about 210
it’s atomic # is 85
astatine is a very radioactive element
all forms of astatine are radioactive
they’re half lives range from seconds to the longest one which is
about 8 hrs
first produced in 1940 by Dale R. Coson, Kenneth Ross Mackenzie
and Emilio Segrè at the University of California, Berkeley.
bombarded bismuth with alpha particles
was found naturally 3 years later
At any given time, about 25 grams of naturally occurring astatine
exists on our planet.
Its properties are inferred from its position in the periodic table and by
studying its chemistry in extremely dilute solutions.
Classification:
Astatine is a halogen and a
nonmetal
LE
T
C
K
C
Q
UI
FA
T
AB
Color:
Presumed very dark
Atomic weight:
(210), no stable isotopes
State:
solid
Melting point:
302 oC, 575.2 K
Boiling point:
337 oC, 610 K
Electrons:
85
Protons:
85
Neutrons in most abundant
isotope:
125
Electron shells:
2,8,18,32,18,7
Electron configuration:
[Xe] 4f14 5d10 6s2 6p5
Density @ 20oC:
7 g/cm3 approx.
Citation Page
"Iodine." World of Scientific Discovery. Gale, 2007. Student Resources in Context. Web. 1 Dec. 2014.
"Iodine." Chemical Elements. David E. Newton. Ed. Kathleen J. Edgar. 2nd ed. Detroit: UXL, 2010. Science in Context. Web. 1
Dec. 2014.
"Halogens." World of Chemistry. Gale, 2000. Science in Context. Web. 1 Dec. 2014
<a href="http://www.chemicool.com/elements/astatine.html">Astatine</a>
http://education.jlab.org/itselemental/ele035.html>Bromine</b>
Fluorine
http://ic.galegroup.com/ic/suic/ReferenceDetailsPage/ReferenceDetailsWindow?failOverType=&query=&prodId=SUIC&windowstate=normal&contentModules=&displayquery=&mode=view&displayGroupName=Reference&limiter=&u=want68409&currPage=&disableHighlighting=false&displayGroups=&sortBy=&source=&search_within_results=&p
=SUIC&action=e&catId=&activityType=&scanId=&documentId=GALE%7CCV2646000456
Chlorine
http://school.eb.com/levels/high/article/82243