2.6 & 2.7 describe the reactions of these elements with water and understand that the reactions provide a basis for their recognition as a family of elements

Group 1 elements

Group 1 elements react vigorously with water to give an alkaline solution of the metal hydroxide as well as hydrogen gas. As we go down the group the elements are more reactive. 

When these elements are reacted with water, the following observations can be seen:

Lithium

• Moves around the surface of the water
• Hissing sound
• Bubbles of gas
• Gets smaller and smaller: eventually disappears

Sodium

• Moves around the surface of the water
• Hissing sound
• Bubbles of gas
• Melts into a shiny ball
• Gets smaller and smaller: eventually disappears

Potassium

• Moves around the surface of the water
• Hissing sound
• Bubbles of gas
• Melts into a shiny ball
• Burns with a lilac-coloured flame
• Gets smaller and smaller: eventually disappears

Trends show that the further down the group we get, the more reactive the elements are.