group 7 save my exams

• What are the elements in Group 7 known as?

  Halogens
• Name the halogens.

  Fluorine, chlorine, bromine, iodine, astatine

  
• What type of elements are halogens?

  Non-metals that are poisonous
• Why do halogens have similar reactions?

  They each have seven electrons in their outermost shell
• What does it mean that halogens are diatomic?

  They form molecules of two atoms
• What happens to the melting and boiling points of halogens as you go down the group?

  They increase as you go down the group

  
• Why do melting and boiling points increase down the group?

  Due to increasing intermolecular forces
• What are the physical states of halogens at room temperature?

  Fluorine and chlorine are gases, bromine is liquid, iodine is solid

  
• How do the colors of halogens change as you descend the group?

  They become darker
• What is the test for chlorine gas?

  Damp blue litmus paper bleaches white
• What happens to litmus paper when chlorine gas is present?

  It may turn red briefly before bleaching
• Why should chlorine be handled in a fume cupboard?

  Due to its toxicity
• What do halogens form when they react with metals?

  Ionic compounds called metal halide salts
• What charge does the halide ion carry?

  -1 charge
• How does reactivity change among halogens down the group?

  Reactivity decreases moving down the group
• What happens to the rate of reaction for halogens further down the group?

  The rate of reaction is slower
• What do halogens form when they react with nonmetals?

  Simple molecular covalent structures
• What happens when hydrogen chloride gas dissolves in water?

  It forms hydrochloric acid
• How do hydrogen halides behave in water?

  They dissolve to form strongly acidic solutions
• What is unique about hydrofluoric acid compared to other hydrogen halides?

  It is a weak acid in water
• How does reactivity change with hydrogen halides down the group?

  Reactivity decreases down the group
• What happens to the stability of hydrogen halides as you go down the group?

  They become less stable
• What principle about stability and reactivity is illustrated by halogen reactions?

  The more vigorous a reaction, the more stable the product
• What is a halogen displacement reaction?

  A more reactive halogen displaces a less reactive halogen
• Which halogen is the most reactive?

  Chlorine
• What happens when chlorine is added to potassium bromide solution?

  It becomes orange as bromine is formed

  
• What happens when chlorine is added to potassium iodide solution?

  It becomes brown as iodine is formed

  
• What does bromine do to potassium iodide?

  It displaces iodine from the solution
• What can be predicted about fluorine's reactivity?

  It will displace all other halogens
• What can be predicted about astatine's reactivity?

  It will be displaced by all halogens
• Why is astatine rarely tested in reactions?

  It is the rarest naturally occurring element
• What is the relationship between oxidation and reduction in halogen displacement reactions?

  Oxidation is loss of electrons, reduction is gain
• What are spectator ions in a reaction?

  Ions that do not change during the reaction
• What happens to chlorine atoms in the displacement reaction?

  They are reduced as they gain electrons
• What happens to iodide ions in the displacement reaction?

  They are oxidized as they lose electrons
• What is the significance of displacement reactions in terms of redox processes?

  They illustrate oxidation and reduction occurring together
• What are displacement reactions also known as?

  Single replacement reactions
• How do halogen atoms gain electrons during reactions?

  They form -1 ions called halide ions

  
• How does the number of electron shells change down Group 7?

  The number of shells increases
• What happens to the attraction between the nucleus and outer shell as you go down the group?

  It decreases