Group 7
The HalogensBy: Kiera O'Gorman, Amanda Murphy, and Tyler Lauria
The halogens consist of five non-metallic elements. They are found in group 17 of the periodic table, in the second column from the right.

Compounds that contain halogens are called salts, such as NaCL. The elements included are fluorine (F), chlorine (Cl), bromine (Br),iodine (I), and astatine (At).

As you travel down the group, the electronegativity falls because of the increase in the elements' sizes.

external image halog.gif
The halogens cannot be found in nature by themselves because of their high rate of reactivity. Fluorine is the most reactive, and the reactivity decreases as you go down the column until you reach astatine, which is the least reactive halogen.

The outer shells of all halogens have seven electrons and an oxidation number -1.

external image Halogens.jpg
Here's a video of some reactions that take place when using halogen gases!

  • external image F-en.h36.jpg
    Name: Fluorine
  • Symbol: F
  • Atomic Number: 9
  • Atomic Weight: 18.9984032
  • Color: Pale Yellow
  • Melting Point: -219.6 oC
  • Boiling Point: -188.1 oC
  • Electron Configuration: 1s22s22p5
  • History: Fluorine was isolated by Henri Moissan in 1886. During the 1600's, the minerals used to etch glass contained fluorine (but no one knew at that time). Fluorine was discovered when scientists were trying to find an element that would be able to attack glass. Its name comes from the greek root 'fluere' which means flow.
  • Today: Fluorine is used in toothpaste highly in our day today. It can also be found in water systems because of their assistance in preventing tooth decay.

external image 300-chlorine.jpg
  • Name: Chlorine
  • Symbol: Cl
  • Atomic Number: 17
  • Atomic Weight: 35.453
  • Color: green/yellow
  • Melting Point: -101 oC
  • Boiling Point:-34 oC
  • Electron Configuration: 1s22s22p63s23p5
  • History: Chlorine was declared an element by Davy in 1810. Chlorine was also used during World War I as a poisonous gas. Its name comes from the greek root 'chloros' which means greenish-yellow
  • Today: Chlorine can commonly be found in swimming pools in order to keep them clean. Poorly kept pools will allow you to smell the foul odor of chlorine.

external image Bromine.jpg
  • Name: Bromine
  • Symbol: Br
  • Atomic Number: 35
  • Atomic Weight: 79.9
  • Color: red/brown
  • Melting Point:-7 oC
  • Boiling Point: 58.9 oC
  • Electron Configuration: [Ar] 3d104s24p5
  • History: Bromine was isolated in 1826 by Balard. It used to be added to gasoline to help the engine. Its name comes from the greek root 'bromos' which means stench.
  • Today: Bromine is now only used for dying, disinfecting, and with photographic chemicals. It is extremely dangerous and will burn the skin with contact.

external image RTEmagicC_799px-Iodine-sample.jpg.jpg
  • Name: Iodine
  • Symbol: I
  • Atomic Number: 53
  • Atomic Weight: 126.9
  • Color: blue/black solid, purple gas
  • Melting Point: 113.5 oC
  • Boiling Point: 184 oC
  • Electron Configuration:[Kr]4d105s25p5
  • History: Courtois discovered iodine in 1811. Its name comes from the greek root 'ioeides' which means violet-colored.
  • Today: Iodine is found in seaweed and brines, and is needed in the human diet for a person to function properly. It is also used with the treatment of thyroid gland problems.

external image astatine.jpg
  • Name: Astatine
  • Symbol: At
  • Atomic Number: 85
  • Atomic Weight: 210
  • Color: very dark
  • Melting Point: 302 oC
  • Boiling Point: 337 oC
  • Electron Configuration: [Xe]4f145d106s26p5
  • History: Astatine was first produced by Corson and others from UCLA in 1940. Its name comes from the greek root 'astatos' which means unstable
  • Today: There is not much that we know about Astatine, but it is predicted that it will act like the other halogens.

This video sings all about the halogens!

Go here to learn more about the halogens:

Multiple Choice Questions:

1. Put these elements in order from most reactive to least reactive
A. Chlorine, Bromine, Iodine, Fluorine, Astatine
B. Astatine, Iodine, Bromine, Chlorine, Fluorine
C. Fluorine, Bromine, Iodine, Chlorine, Astatine
D. Fluorine, Chlorine, Bromine, Iodine, Astatine

2. Why can't the halogens be found on their own in nature?
A. They are all man-made
B. They don't exist
C. They all have high rates of reactivity
D. They can be found in nature

3. What is the oxidation number of a halogen?
A. -1

4. What did fluorine used to be used in?
A. cleaning pools
B. preventing tooth decay
C. glass etching
D. cleaning wounds

5. What body part can be helped with iodine?
A. Spleen
B. Kidney
C. Liver
D. Thyroid

Works Cited
"Atomic and Physical Properties of Periodic Table Group 7 (the Halogens)." Atomic and Physical Properties of Periodic Table Group 7 (the Halogens). N.p., n.d. Web. 28 . Nov. 2012. <>.

"Classifying: Calm the Chaos." Classifying: Calm the Chaos. N.p., n.d. Web. 28 Nov. 2012 <>.

"Fluorine Element Facts." Chemicool. N.p., n.d. Web. 28 Nov. 2012. <>.

"Halogen Element (chemical Element Group)." Encyclopedia Britannica Online. Encyclopedia Britannica, n.d. Web. 28 Nov. 2012. <>.

"Halogens on the Right." Elements & Periodic Table: Halogens. N.p., n.d. Web. 28 Nov. 2012. <>.