Slides in this set
TRENDS IN REACTIVITY
· As you go down the group, the ionisation energies of
the group 2 elements decrease s due to the increasing
atomic radius and shielding effect.
· This causes the reactivity of group 2 metals to
increase, as when they react they lose electrons in
order to form cations, meaning that the easier it is to
lose electrons (i.e. the lower the first and second
ionisation energies) the more reactive the element
will be.…read more
REACTIONS WITH WATER AND OXYGEN
· When group 2 elements react, they are oxidised from an oxidation state of 0 -> +2 forming 2+
· Half equation:
Ca Ca 2+ + 2e--
· Reactions with water:
· When group 2 elements react with water, they produce a metal hydroxide and hydrogen.
· Half equation:
M + H2O M(OH)2 + H2
· Reactions with oxygen:
· When group 2 elements react with oxygen they form solid white oxides.
· Half equations:
2M + O2 2MO…read more
GROUP 2 OXIDES AND HYDROXIDES
· Group 2 oxides and hydroxides are bases they form alkaline
solutions in water.
· The oxides of the group 2 metals react readily with water to
form metal hydroxides which dissolve.
· The hydroxide ions OH- make these solutions alkaline.
CaO + H2O Ca 2+ + 2OH-
· APART FROM MAGNESIUM OXIDE which is so unsoluble that the
ions do not dissolve.
· Oxides form stranger alkaline solutions as you move down the
GROUP 2 CARBONATES
· The thermal stability of carbonates changes down the
· Thermal decomposition is when a substance breaks down
· The amount of heat needed to decompose a group 2
element increases causing the thermal stability to increase
down the group.
· Group 2 carbonates decompose to form the oxide and
MCO3 MO + CO2…read more