group 2 Flashcards
Describe the group 2 trend and you go down the group
The shielding increases
The Atomic radius increases
The nuclear attraction on outer electrons decreases
The ionisation energy decreases
What are the observations when you react group to elements with oxygen?
Bright white light
White solid formed
What is the equation for a reaction between a group 2 metal and water?
M(s) + 2H2O(l) ->M(OH)2 (aq) + H2 (g)
How would you rest the identity of the gas (hydrogen) formed between a group 2 metal and water ?
Use a lit splint —> hear a squeaky pop
What happens when a group 2 metal reacts with water in terms of electrons?
the metal loses 2 electrons and becomes a metal 2+ ion
what observations are made in a reaction between a metal and water
Fizzing , Metal dissolves
As you go down group 2 the fizzing and dissolving happens quicker
What is the formal for a metal hydroxide
M(OH)2
What happens to the solubility of group 2 hydroxides as you go down the group?
Increases and ph increases
what happens when a group 2 metal reacts with acids?
The metal loses 2 electrons and becomes a metal 2+ ion
What is the formula for the reaction between a group 2 metal and HCL
M(s) + 2HCL(aq) -> MCL2 (aq) + H2 (g)
MCL2 = salt
what is an acid
a proton (h+) donor
what is a base
a proton (h+) acceptor
what are the different types of bases
metal oxides
metal carbonates
metal hydroxide
group 2 compound with acids
MO and M(OH)2 are bases
most are soluble in water so alkalise
bases react with acids to form a salt
these are now neutralisation reactions
What are the uses of group 2 elements and compounds
Mg(OH)2
Neutralised excess stomach acid (HCL)
Medicine
Equation :
Mg(OH)2 + 2HCL -> MgCl2 + 2H2O
Used of Ca(OH)2
Neutralises acidic soils (H2SO4)
Agriculture
Equation :
Ca(OH)2 + H2SO4 -> CaSO4 + 2H2O
Uses of CaCO3
Calcium carbonate
Thermal decomposition gives CaO which is used to make cement
Equation :
heat
CaCO3 ———> CaO + CO2
