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 pairs of atoms
• What happens to the physical states of halogens at room temperature?

  They exist in different states and colours
• What are the physical properties of the halogens at room temperature?

  • Fluorine: Yellow gas, very reactive
  • Chlorine: Pale yellow-green gas, reactive and dense
  • Bromine: Red-brown liquid, dense and volatile
  • Iodine: Grey solid, shimmery and crystalline

  
• How do the melting and boiling points of halogens change down the group?

  They increase as you go down the group
• Why do melting and boiling points increase down Group 7?

  Due to increasing intermolecular forces
• What is the physical state of fluorine at room temperature?

  Gas
• What is the physical state of bromine at room temperature?

  Liquid
• What is the physical state of iodine at room temperature?

  Crumbly solid
• How does the colour of halogens change as you go down the group?

  They become darker
• What do halogens react with to form metal halides?

  Some metals
• What charge does the halide ion carry?

  -1 charge
• What is the reaction of sodium with chlorine?

  2 Na + Cl → 2 NaCl
• What is the reaction of calcium with bromine?

  Ca + Br → CaBr
• How does reactivity change down Group 7?

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

  It becomes slower
• What forms when sodium donates its outer electron to chlorine?

  An ionic bond is formed

  
• What do halogens form when they react with non-metals?

  Simple molecular covalent structures
• How does reactivity with hydrogen change down the group?

  Iodine reacts less vigorously than chlorine
• What is a halogen displacement reaction?

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

  Chlorine
• Which halogen is the least reactive?

  Iodine
• 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 is the reaction of chlorine with potassium bromide?

  Cl + 2KBr → 2KCl + Br
• What is the reaction of chlorine with potassium iodide?

  Cl + 2KI → 2KCl + I
• What is the reaction of bromine with potassium iodide?

  Br + 2KI → 2KBr + I
• What are the displacement reactions of the halogens?

  • Chlorine displaces bromide ions
  • Chlorine displaces iodide ions
  • Bromine displaces iodide ions
• What are displacement reactions also known as?

  Single replacement reactions
• What happens to the attraction between the nucleus and outer shell as you go down Group 7?

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

  It increases
• What happens to halogen reactivity as the distance from the nucleus increases?

  Reactivity decreases
• Why is fluorine the most reactive halogen?

  Its outermost shell is closest to the nucleus
• What happens to the forces of attraction between the nucleus and outer shell as you go down the group?

  They decrease
• What makes it harder for halogens to gain electrons as you descend the group?

  Increased distance from the nucleus
• What are the trends in reactivity for Group 7 elements?

  • Reactivity decreases down the group
  • Fluorine is the most reactive
  • Iodine is the least reactive
• What are the electronic configurations of Group 7 elements?

  • All have 7 electrons in outer shell
  • Form -1 ions when gaining an electron
  • Reactivity trends explained by electron configurations