Group 2 Flashcards
What happens if you mix a group 2 oxide with water
It forms a metal hydroxide
What happens if you mix a group 2 metal with water
It forms a metal hydoxide and hydrogen
How do you prove that group 2 metals are redox reaction in terms of oxidation numbers
oxidation numbers- ____ increases from ___ to ___so it has been oxidised
____ decreases from ___ to ___ so has been reduced
How do you prove that group 2 metals are redox reactions in terms of electrons (using magnesium and copper as an example )
Mg–> Mg2+ + 2e- so has been oxidised as it has lost electrons
Cu2+ + 2e- —> Cu so it has been reduced as it has gained electrons
Why does the pH of group 2 hydroxides increase down the group
The hydroxides made are partially soluble
The solubility of group 2 hydroxides increases down the group
Therefore the pH of group 2 hydroxides increases down the group and becomes more alkaline
What would Sr(OH)2 Ba(OH)2 Mg(OH)2 , Ca(OH)2 , be ranked in solubility
Mg (OH)2
Ca(OH)2
Sr(OH)2
Ba(OH2)
because going down the group solubility increases as well as alkalinity
What type of agents are group 2 metals and why
They are reducing agents as they cause either species to gain electrons. This is because they lose 2 outer electrons to form 2+ ions as the third ionisation energy is too large
What do you say when it asks to describe and explain the trend in reactivity down group 2 for 3 marks
Reactivity increases down the group as the atomic radius increases so shielding increases
These outweigh the increases in nuclear charge
Therefore the nuclear attraction on the outer electrons decrease
This makes it easier to lose the outer electrons so the metals get more reactive down the group
DONT SAY THIS FOR ANY GROUPS EXCEPT GROUP 2 PREETY
State 2 uses of a group 2 compound
Calcium carbonate is used to neutralise stomach acid
Calcium hydroxide is used to neutralise acidic soils
What are the equations for calcium carbonate neutralising stomach acid and calcium hydroxide neutralising acidic soils
CaCO3+ 2HCl–> CaCl2+ CO2+H20
Ca(OH)2 +2H+ –> Ca2+ + 2H20
What happens when you react a group 2 metal with oxygen
A metal oxide forms
It forms a giant ionic structure
What happens when you react a group 2 metal with water
An alkaline hydroxide forms
Effervescence is more vigorous and solid dissolves faster including a comparison of relative reaction
The reaction becomes more vigorous down the groups because reactivity increases down the group
What happens when you react a group 2 metal with a dilute acid
A salt and hydrogen forms
What happens when you react a group 2 oxide with water
An alkaline solution of a hydroxide is formed
The solubility of the hydroxides increase down the group so the solutions formed become more alkaline so the pH increases so theres more hydroxide ions released into the solution
What are the observations when adding calcium to water
Effervescence and solid dissolves
