The group 1 elements are reactive, soft metals

• The alkali metals are lithium, sodium, potassium, rubidium, caesium and francium

• They all have one electron in their outer shell which makes them very reactive and gives them similar properties

• The alkali metals are all soft and have low density

• The trends for the alkali metals as you go down Group 1 include:

  • Increasing reactivity

    • The outer electron is more easily lost as the attraction between the nucleus and electron decreases, because the electron is further away from the nucleus and the further down the group you go

  • Lower melting and boiling points

  • Higher relative atomic mass

Alkali metals form ionic compounds with non-metals

• The Group 1 elements don’t need much energy to lose their one outer electron to form a full outer shell, so they readily form 1+ ions

• It’s so easy for them to lose their outer electron that they only ever react to form ionic compounds.

• These compounds are generally white solids that dissolve in water to form colourless solutions

• Reaction with water

  • When Group 1 metals are put in water, they react vigorously to produce hydrogen gas and metal hydroxide

    • Salts that dissolve in water to produce alkaline solutions

  • The more reactive(lower down in the group) an alkali metal is, the more violent the reaction

  • Sodium + Water - Sodium Hydroxide + Hydrogen

  • 2Na + 2H20 - 2NaOH + H

• Reaction with chlorine

  • Group 1 metals react vigorously when heated in chlorine gas to form white chloride salts

  • As you go down the group, reactivity increases so the reaction with chlorine gets more vigorous

  • Sodium + Chlorine - Sodium Chloride

  • 2Na + Cl - 2NaCl

• Reaction with oxygen

  • The Group 1 metals can react with oxygen to form a metal oxide:

  • Different types of oxide will form depending on the Group 1 metal:

    • Lithium reacts to form lithium oxide

    • Sodium reacts to form a mixture of sodium oxide(Na20) and sodium peroxide(Na2O2)

    • Potassium reacts to form a mixture of potassium peroxide(K202) and potassium superoxide(K02)

Group 1 metals have different properties to transition metals

• Group 1 metals are much more reactive than transition metals-they react more vigorously with water, oxygen or Group 7 elements, for example

• They’re also much less dense, strong and hard than the transition metals, and have much lower melting points

  • e.g. manganese melts at 2000C

  • Sodium melts at 98C