Unit #1Unit #2Unit #3Unit #4Unit #5Unit #6Unit #7Unit #8Unit #9Unit #10
spacerUNIT # 4  
spacerspacerIntroduction
spacerspacerObjectives
spacerspacerReading


spacer4.1 The Periods
spacer4.2 The Groups
spacerGroup IA - Alkali metals
spacerGroup IIA - Alkaline earth metals
spacerGroup VIIA - Halogens
spacerGroup VIIIA - Noble gases
spacer4.3 Metals,
spacerNonmetals,
spacerSemimetals

spacerProperties of Metals
spacerProperties of Nommetals
spacerProperties of Semimetals
spacerSummary
spacer4.4 Metallic
spacerBonding

spacer4.5 Octet
spacerRule

spacer4.6 Ions
spacer
4.7 Covalent
spacerBonding

spacerCovalent Bonding & Groups
spacer
4.8 Atomic
spacerSize

spacer
4.9 Ionic
spacerSize

spacerIonic Size of Metal Ions
spacerIonic Size of Nonmetal Ions
spacerIonic Size for Isoelectronic Series
spacer
4.10 mp/bp
spacerTrends
spacer
4.11 Metallic
spacerTrend


spacer** More
spacerspacerperiodic
spacerTrends
**


spacerspacerProblems
spacer1 | 2 | 3
spacerspacerCrossword
spacerspacerHow well do you
spacerknow your
spacerPeriodic Table?

Unit #4 THE PERIODIC TABLE

4.2 - The Groups

4.2.3 - The Halogens

The halogens: F, Cl, Br, I, and At

View the halogen.
Physical
Properties:
  • fluorine, a pale yellow gas
  • chlorine, a greenish gas, has an irritating odor
  • bromine, a red-brown liquid at room temperature
  • iodine, a dark grey crystalline solid at room temperature
Chemical
Properties:
  • the halogens exist as diatomic gas molecules (section 4.7)
  • all halogens have seven valence electrons (section 3.3) which form ions with a negative (-1) charge
  • fluorine is the most reactive of all the nonmetals
  • iodine sublimes (section 2.1) when heated
Abundance:
  • bromine is obtained by processing brine from wells and from seawater
  • iodine is obtained from brine wells and sea plants such as kelp
  • astatine is radioactive. Less than 30 grams exist in the Earth's crust. For greater quantities, this element needs to be synthesized in a laboratory.
Common
Compounds
and Usages:
  • fluorine is the source to produce fluorocarbons such as Freon-12, that are still used as refrigerants in air conditioners.
  • fluorine is a key ingredient in teflon, a fluorocarbon polymer
  • chlorine, in low level, is used to purify drinking water. In high concentrations, it is poisonous
  • chlorine is used in production of paper, textiles, bleaches, medicines, insecticides, paints, plastics
  • bromine is used in photographic chemicals, dyes, fire retardants and in pharmaceutical products
  • iodine compounds are used in producing iodized salt, photographic chemicals and in medicines
  • iodine is required in human body in order to make the hormone thyroxin

Follow this interesting link to see more pictures of the elements:


Section 5.2
The Periodic Table Periods and Groups ..p106

Section 5.3
General Characteristics of the Groups ..p109

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