Group 1 (Alkali Metals)

• What are the Group 1 metals known as?

  Alkali metals
• What do Group 1 metals form when they react with water?

  Alkaline solutions
• Which elements are classified as alkali metals?

  Lithium, sodium, potassium, rubidium, caesium, francium
• Why do alkali metals share similar chemical properties?

  They each have one electron in their outermost shell
• What are the characteristic properties of alkali metals?

  • Soft metals, easily cut with a knife
  • Low densities and low melting points
  • Very reactive, needing to lose one electron to stabilize
• Where are alkali metals located in the periodic table?

  First column on the far left
• What does the reaction of Group 1 metals with water demonstrate?

  Evidence for categorizing them into the same chemical family
• What is the general reaction pattern of Group 1 metals with water?

  Group 1 metal + water ⟶ metal hydroxide + hydrogen
• What is the general formula for the reaction of Group 1 metals with water?

  2M (s) + 2H₂O (l) ⟶ 2MOH (aq) + H₂ (g)
• What do the hydroxides formed by alkali metals in water look like?

  Colourless, aqueous solutions
• Why are alkali metals named so?

  They form alkalis in water
• How does the reactivity of alkali metals with water change down the group?

  It becomes more vigorous
• What are the reactions of the first three alkali metals with water?

  • Lithium: Slow reaction, fizzing, moves on water surface
  • Sodium: More vigorous fizzing, moves rapidly, dissolves quickly
  • Potassium: Burns with lilac flame, very rapid movement, dissolves very quickly
• What is the reaction of lithium with water?

  2Li (s) + 2H₂O (l) ⟶ 2LiOH (aq) + H₂ (g)
• What is the reaction of sodium with water?

  2Na (s) + 2H₂O (l) ⟶ 2NaOH (aq) + H₂ (g)
• What is the reaction of potassium with water?

  2K (s) + 2H₂O (l) ⟶ 2KOH (aq) + H₂ (g)
• What happens to alkali metals when they react with oxygen?

  They form metal oxides and tarnish
• What are the reactions of the first three alkali metals with oxygen?

  • Lithium: 4Li (s) + O₂ (g) ⟶ 2Li₂O (s)
  • Sodium: 4Na (s) + O₂ (g) ⟶ 2Na₂O (s)
  • Potassium: 4K (s) + O₂ (g) ⟶ 2K₂O (s)
• What are the physical trends in alkali metals?

  • Soft and easy to cut, getting softer down the group
  • Less dense than water
  • Low melting points decrease down the group
• What causes the decrease in melting points of alkali metals?

  Decreasing attractive forces between outer electrons and positive ions
• What is predicted about rubidium's reactivity compared to potassium?

  It will react more vigorously
• What predictions can be made about rubidium's properties?

  • Soft grey solid
  • Shiny when freshly cut
  • More dense than potassium (> 0.86 g/cm³)
  • Lower melting point than potassium (< 63.5 °C)
• How does the reactivity of alkali metals change from lithium to francium?

  Reactivity increases from lithium to francium
• What is the significance of trends in chemistry?

  They indicate patterns of behavior in elements
• What is the least reactive alkali metal?

  Lithium
• What is the most reactive alkali metal?

  Francium
• What would be good descriptors for rubidium's reaction with water?

  Explosively and violently