Group 2 Flashcards
What is the reaction between Mg and oxygen?
2Mg (s) + O2 (g) —–> 2MgO (s)
-burns easily
-bright white flame
What is the reaction between Mg and water?
Mg (s) + H2O (l) ——> Mg(OH)2 (s) + H2 (g)
-vigorous reaction with steam
-very slow reaction with water
What is the reaction between Ca and oxygen?
2Ca (s) + O2 (g) ——> 2CaO (s)
-difficult to ignite
-red flame
What is the reaction between Ca and water?
Ca (s) + O2 (g) ——> Ca(OH)2 (s) + H2 (g)
- reacts moderately
- hydroxide formed
What is the reaction between Sr and oxygen?
2Sr (s) + O2 (g) ——> 2SrO (s)
Sr (s) + O2 (g) ——> SrO2 (s)
-difficult to ignite
-red flame
What is the reaction between Sr and water?
Sr (s) + 2H2O (l) → Sr(OH)2 (aq) + H2 (g)
-reacts rapidly
-hydroxide produced
What is the reaction between Ba and oxygen?
2Ba (s) + O2 (g) → 2BaO (s)
Ba (s) + O2 (g) → BaO2 (s)
-difficult to ignite
-green flame
What is the reaction between Ba and water?
Ba (s) + 2H2O (l) → Ba(OH)2 (aq) + H2 (g)
-reacts vigorously
-hydroxide formed
What is the reaction between Ba and dilute HCl?
Ba (s) + 2HCl (aq) → BaCl2 (aq) + H2 (g)
-reacts vigorously
What is the reaction between Ba and dilute H2SO4?
Ba (s) + H2SO4 (aq) → BaSO4 (s) + H2 (g)
-reaction is quickly stopped by the formation of an insoluble sulfate layer on the metal surface
What is the reaction between Sr and dilute H2SO4?
Sr (s) + H2SO4 (aq) → SrSO4 (s) + H2 (g)
-reaction is quickly stopped by the formation of an insoluble sulfate layer on the metal surface
What is the reaction between Sr and dilute HCl?
Sr (s) + 2HCl (aq) → SrCl2 (aq) + H2 (g)
-reacts vigorously
What is the reaction between Ca and dilute HCl?
Ca (s) + 2HCl (aq) → CaCl2 (aq) + H2 (g)
-reacts vigorously
What is the reaction between Ca and dilute H2SO4?
Ca (s) + H2SO4 (aq) → CaSO4 (s) + H2 (g)
-reaction is slowed by the formation of a sparingly soluble sulfate layer which coats the metal surface stopping hydrogen bubbles from rising
What is the reaction between Mg and dilute H2SO4?
Mg (s) + H2SO4 (aq) → MgSO4 (aq) + H2 (g)
-reacts vigorously
What is the reaction between Mg and dilute HCl?
Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g)
-reacts vigorously
All group 2 oxides basic?
yes all except BeO which is amphoteric
What is thermo decomposition?
the breakdown of a compound into two or more different substances using heat
When do group 2 carbonates break down (decompose)
when they are heated to form the metal oxide and give off carbon dioxide gas
What does thermal stability do when going down the group
increases
-The smaller positive ions at the top of the groups will polarise the anions more than the larger ions at the bottom of the group
The small positive ion attracts the delocalised electrons in the carbonate ion towards itself
The higher the charge and the smaller the ion the higher the polarising power
-The more polarised they are, the more likely they are to thermally decompose as the bonds in the carbonate and nitrate ions become weaker
What does melting point do going down the group
decreases
-the ionic radius of the metal ion increases
-This results in a weaker electrostatic attraction between the delocalised electrons and the positive nuclei
What does first ionisation energy do going down the group
decreases
-The atomic radius and shielding effects down groups are greater than the nuclear charge effect, leading to an overall decrease in ionisation energies as you move down group 2.
Does reactivity increase going down group 2? Explain
yes it does
-Since it becomes easier to remove electrons further down the group, the reactivity of group 2 metals increases
