(a(i))[1]
Describe the pattern in the relative hardness of the Group I elements.
(a(ii))[1]
Predict the melting point of rubidium.
(a(iii))[1]
Explain why it is hard to predict the density of caesium.
(b(i))[1]
When potassium reacts with water, it floats and melts into a ball. A flame is seen. What colour does potassium give to the flame?
(b(ii))[1]
Use the information in the table to suggest why potassium floats on water.
(b(iii))[1]
Hydrogen is produced when potassium reacts with water. Complete the dot-and-cross diagram to show the electron arrangement in a molecule of hydrogen.