Periodic Table Groups

• What are the three classifications of elements based on their position in the periodic table?

  Alkali metals (group 1), halogens (group 7), and noble gases (group 0)
• Why can elements be classified into specific groups like alkali metals or halogens?

  Because they have the same number of electrons in their outer shell
• What determines the chemical properties of elements in the periodic table?

  Their position in the periodic table
• What are the physical characteristics of alkali metals?

  They are soft and have relatively low melting points
• What happens when lithium, sodium, and potassium react with water?

  They react vigorously to create an alkaline metal hydroxide and hydrogen
• What is the pattern in reactivity of alkali metals with water?

  • Lithium: fizzes steadily
  • Sodium: melts into a ball then fizzes quickly
  • Potassium: gives off sparks and hydrogen burns with a lilac flame
  • Reactivity increases down the group
• How does the reactivity of alkali metals change as you go down the group?

  The reactivity increases down the group
• Why is it easier to lose electrons as you go down the alkali metal group?

  Due to the increase in electron shells and more electron shielding
• What is the effect of electron shielding on the attraction between the nucleus and outer shell electrons?

  It decreases the attraction
• What are cations and how are they formed in metals?


  Cations are positive metal ions formed when metals react
• What happens to the attraction between the nucleus and outer shell electrons as you go down the alkali metal group?

  The attraction decreases
• What is the physical state and color of chlorine at room temperature?

  Chlorine is a yellow-green gas
• What is the physical state and color of bromine at room temperature?

  Bromine is a red-brown liquid
• What is the physical state and color of iodine at room temperature?

  Iodine is a purple solid
• What is the trend in physical states of halogens as you move down the group?

  • The trend is from gas to liquid to solid.
  • This is due to increasing melting and boiling points as you go down the group.
• Based on the trend in physical states, what can you predict about halogens above chlorine?

  Halogens above chlorine will be gases
• Based on the trend in physical states, what can you predict about halogens below iodine?

  Halogens below iodine will be solids
• What happens to damp litmus paper when it is exposed to chlorine gas?

  The damp litmus paper is bleached and turns white
• How do halogens react with metals to form metal halides?

  • Halogens react with metals to form ionic compounds.
  • The halide ion carries a -1 charge.
  • Example: NaCl or MgBr₂ (where Mg has a +2 charge).
• How does the reactivity of halogens change as you move down group 7?


  The reaction is less vigorous as you move down group 7
• What is the general reaction of halogens with hydrogen?

  • Halogen + Hydrogen → Hydrogen Halide (e.g., HCl, HBr, HI).
  • The reaction becomes less vigorous down the group.
• What happens to hydrogen halides when they dissolve in water?

  They produce acidic solutions and fully dissociate into H⁺ and halide ions
• How does the reactivity of halogens relate to their displacement reactions with halide ions?

  • A more reactive halogen can displace a less reactive one in an aqueous solution.
  • Example: Chlorine displaces bromine in potassium bromide solution.
• Which halogens can displace each other in displacement reactions?

  Chlorine can displace bromine and iodine; bromine can displace iodine; iodine cannot displace chlorine or bromine
• What happens to the reactivity of halogens as you go down the group?

  • Reactivity decreases as you go down the group.
  • This is due to increased distance from the nucleus and increased electron shielding.
• What does OILRIG stand for in the context of redox reactions?

  • OILRIG stands for Oxidation Is Loss, Reduction Is Gain (of electrons).
• In a displacement reaction, what happens to the more reactive halogen?

  The more reactive halogen is reduced as it gains electrons
• In a displacement reaction, what happens to the less reactive halogen?

  The less reactive halogen is oxidized as it loses electrons
• How do electronic configurations explain the relative reactivity of halogens?

  • Electronic configurations show an increase in electron shells down the group.
  • Greater shielding and weaker attraction lead to reduced reactivity.
• What is the electronic configuration of fluorine?

  Fluorine: 2,7
• What is the electronic configuration of chlorine?

  Chlorine: 2,8,7
• Why are noble gases considered chemically inert compared to other elements?

  Because they have full outer shells of electrons.
• What is the electronic configuration of noble gases?

  Noble gases have 8 electrons in their outer shell, except helium, which has 2.
• How does the full outer shell of noble gases contribute to their stability?

  A full outer shell makes noble gases very stable and unreactive.
• What is one use of helium due to its low density?

  Helium is used in balloons and airships.
• Why do balloons filled with helium float upwards?

  Because helium is much less dense than air.
• How does the inertness and non-flammability of noble gases benefit their use in light bulbs?

  They prevent the filament from burning away.
• What noble gases are commonly used inside light bulbs?

  Argon, krypton, and xenon.
• Why is argon used as a shield gas during welding?

  Because it is inert and denser than air, keeping it away from the metal.
• What pattern is observed in the boiling points of noble gases as you go down the group?

  The boiling points increase with increasing relative atomic mass.