Topic 4 - Reactivity

THE ACTIVITY SERIES

• The activity series is also known as the reactivity series. 
• The elements at the top of the list are the most reactive.
• The first five are in Groups 1 and 2, the alkali and alkaline earth metals. The sixth element in the list is in Group 3, and the remainder are all in a part of the periodic table that we haven’t looked at yet, the centre section. 

REACTION WITH WATER - METALS IN GROUP 1

• The list can be used to predict how violently each element will react with other substances. 

• 2K + 2H2O = 2KOH + H2
• Potassium plus water reacts to give potassium hydroxide and hydrogen. 

• 2Na(s) + 2H2O(l) = 2NaOH(aq) + H2(g)
• sodium + water sodium hydroxide + hydrogen

• Lithium also reacts readily with water, but with much less violence: 2Li(s) + 2H2O(l) = 2LiOH(aq) + H2(g) 

REACTION WITH WATER

• Ca(s) + 2H2O(l) = Ca(OH)2 (aq) + H2 (g) 
• Calcium reacts with water to form calcium hydroxide and hydrogen. 

• Magnesium reacts very slowly with cold water. Its equation is as follows.
• Mg(s) + 2H2O(l) = Mg(OH)2…