Group 2 Metals Flashcards
What is the trend in atomic radius for group 2 metals?
Atomic radius increases down the Group.
As one goes down the group, the atoms have more
shells of electrons making the atom bigger.
What is the trend in melting point for group 2 metals?
Down the group the melting points decrease. The
metallic bonding weakens as the atomic size
increases. The distance between the positive ions and
delocalized electrons increases. Therefore the
electrostatic attractive forces between the positive
ions and the delocalized electrons weaken.
What is the trend in ionisation energy for group 2 metals?
The outermost electrons are held more weakly because they are successively further from the nucleus in additional shells.
In addition, the outer shell electrons become more shielded from the attraction of the nucleus by the
repulsive force of inner shell electrons
What is the trend in reactivity for group 2 metals?
Reactivity of group 2 metals increases down the group as it is easier for electrons to be lost
How do group 2 metals react with liquid water?
Mg will react with warm water, giving
magnesium hydroxide.
Mg + 2 H2O –> Mg(OH)2 + H2
The other group 2 metals will react with cold water with increasing vigour down the group to form hydroxides.
What is the trend in solubility for group 2 metal hydroxides?
Group II hydroxides become more soluble down the group.
All Group II hydroxides when not soluble appear as white precipitates.
For example, magnesium hydroxide is not very soluble, whilst barium hydroxide would easily dissolve
in water. The hydroxide ions present would make the solution strongly alkaline.
What is the trend in solubility for group 2 metal sulphates?
Group II sulphates become less soluble down the group.
BaSO4 is the least soluble.
What is thermal decomposition?
Thermal decomposition is defined as the use
of heat to break down a reactant into more than
one product
How does thermal decomposition change down the group for group 2 metal carbonates and nitrates?
The ease of thermal decomposition decreases down the group i.e. more energy is required down the group. The reason why this is related to the polarising effect of the group 2 metals on the C-O, down the group the carbonate ion is more stable and less polarised therefore the bonds are not as distorted
Summarise the reaction of magnesium with steam.
Magnesium burns in steam to produce
magnesium oxide and hydrogen. The Mg
would burn with a bright white flame.
Mg (s) + H2O (g) –> MgO (s) + H2 (g)
