Periodic Table - Groups 1 and 7

Group One: Alkaline Metals

• Definition: Group One metals, known as alkaline metals, include Lithium, Sodium, and Potassium.

• Physical Properties:

  • Softness: Can be cut with a knife.
  • Melting Points: Decrease down the group.
  • As you go down the group:
    • Lithium: Higher melting point
    • Sodium: Moderate melting point
    • Potassium: Lower melting point
  • Density: Increases as you move down the group.

• Reactivity with Water:

  • Lithium: Reacts slowly, produces fizzing, moves on the surface.
  • Sodium: Reacts more vigorously; more fizzing and faster movement than lithium.
  • Potassium: Reacts very vigorously, burns with a lilac flame, and moves rapidly.
  • Trend in Reactivity: Increases as you go down the group.
  • Predictions:
    • Rubidium: Violent reaction with sparks.
    • Cesium: Causes violent explosions.
    • Francium: Too reactive to predict.

• Reactivity with Chlorine/Oxygen: Same trend as with water (reactivity increases down the group).