Group 7 Elements C1

• What are the group 7 elements known as?

  Halogens
• Which elements are included in the halogens?

  Fluorine, chlorine, bromine, iodine, and astatine
• Why are chlorine, bromine, and iodine the most studied halogens?

  They react in very similar ways
• Why is fluorine not studied much in reactions?

  It is extremely reactive
• What is the state of astatine at room temperature?

  It is radioactive and disappears within minutes
• What are the key properties of halogens?

  • All are poisonous
  • All are nonmetals
  • They have colored vapors when gaseous
  • They are covalent elements
  • They have low melting and boiling points
• What type of bonds do halogens form?

  Covalent bonds
• What is the molecular form of chlorine?

  Cl₂
• How do melting and boiling points change as you move down the group of halogens?

  • Melting and boiling points increase
  • Atoms and molecules get larger
  • Greater intermolecular forces due to size
• What are intermolecular forces?

  Weak forces of attraction between molecules
• Why does iodine have a higher melting point than fluorine?

  Iodine has larger molecules and stronger intermolecular forces
• What is the state of iodine at room temperature?

  Solid
• How many electrons do halogens have in their outer shell?

  Seven electrons
• What do halogens need to achieve noble gas configuration?

  They need to obtain one more electron
• Why is fluorine the most reactive halogen?

  It has fewer electron shells, making it easier to attract electrons
• What happens when halogens react with hydrogen?

  They form hydrogen halides
• What is the reaction condition for fluorine with hydrogen?

  Explosive even at negative 200 degrees Celsius and in darkness
• What is the reaction condition for chlorine with hydrogen?

  Explosive in sunlight, slow in darkness
• What is required for bromine to react with hydrogen?

  300 degrees Celsius and a platinum catalyst
• What is the nature of the reaction of iodine with hydrogen?

  Very slow and reversible at 300 degrees Celsius with a catalyst
• What type of compounds do halogens form when reacting with metals?

  • Ionic compounds
  • Often referred to as salts
  • Example: Sodium chloride (table salt)
• What is the reaction of sodium with chlorine?

  Sodium plus chlorine forms sodium chloride
• What is a displacement reaction in the context of halogens?

  • More reactive halogen displaces a less reactive halogen
  • Occurs in solutions of their salts
  • Example: Chlorine displaces bromine from potassium bromide
• What happens when chlorine is added to potassium bromide?

  Chlorine displaces bromine, forming potassium chloride and bromine
• What happens when bromine is added to sodium fluoride?

  No reaction occurs because fluorine is more reactive than bromine
• What indicates that no reaction occurs in a displacement reaction?

  • No color change
  • No formation of new products
  • Reactants remain in solution
• How can students reach out for questions about halogens?

  By sending a direct email or commenting in the box below
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