alkali metals

• group 1

  alkali metals
• electrons

  single electron in outer shell
• reactivity 


  reacts vigorously with water to create alkaline solution and hydrogen
• reactions 


  react with hydrogen to create an oxide
• alkali metals react with .....

  chlorine to form a white precipitate
• reactivity of elements

  increases as you go down the group
• why does reactivity increase as you go down ?

  -outer electron gets further away from the nucleus .

  -attraction between nucleus and outer electron gets weaker

  -so electron is lost more easily
• equation for group 1 metals

  metal + water = metal hydroxide + hydrogen
• group 1 properties

  relatively soft , low melting point

  very reactive because they loose the outer shell electron
• reacting with chlorine

  metal chloride formed

  dissolves in water

  colourless solution produced
• reacting with oxygen 


  rapidly turns from silver shiny to dull

  metal oxide produced
• reacting with water

  metal floats on surface

  melts to create metal hydroxide

  when reacting with water energy released melts the metal
• why does reactivity become more vigorouos as you go down the group?

  atoms gain electron shells

  meaning there are more shells between nucleus and outer shell

  so electron is more easily lost

  then atom is more reactive
• alkali metals get more reactive because ...

  -distance - number of electron shells increase so there is a greater distance between outer shell and nucleus

  strength of attraction - gets weaker because of the distance

  reactivity - the weaker the attraction the easier the electron is lost
• lithium 


  least reactive of alkali metals

  fizzes slowly

  burns a crimson flame when reacted with oxygen

  floats on the surface

  releases bubbles of hydrogen gas

  effervescence
• sodium

  metals floats on the surface

  releasing enough energy to melt sodium

  more reactive than lithium outer electron is less attracted to positively charged nucleus

  turns into molten ball

  burns with a yellow/orange flame when reacted with oxygen
• potassium

  more reactive than lithium and sodium

  outer electron is less attracted to nucleus

  floats and burns with a lilac flame when reacted with oxygen