Group 1

• Group 1 elements are also known as alkali metals
• Why do group 1 elements react similarly?

  All have 1 outer electron and react by losing one electron
• When a group 1 metal is added to water, the following occurs:

  • Bubbles - Hydrogen gas given off
  • Metal disappears
  • Universal indicator turns blue - alkaline solution
  • Metal moves around on the surface - floats Li, Na, K
  • Vigorous reaction/metal ignites
• Reactivity increases down the group because:

  • More electron shells - greater distance between nucleus and outer electron
  • Weaker attraction between outer electron and nucleus
  • Outer electron is easier to lose
• A general balanced equation between a group 1 metal (M) and water:

  2M + 2H20 --> 2MOH + H2
• An example of a balanced equation for the reaction between a group 1 metal (lithium) and water:

  2Li + 2H20 --> 2LiOH + H2
• Peroxides that can form in reactions between a group 1 metal and and oxygen are:

  • $K_2O_2$
  • $Na_2O_2$
• What is a general balanced equation for a reaction between a group 1 metal (M) and oxygen?

  4M + O2 --> 2M(2)O