8.1 Group 2 Flashcards
What are elements in group 2 of the periodic table called?
alkaline earth metals
Which electrons do alkaline earth metals lose when they react?
ns2 + ns1
Why are group 2 metals good reducing agents?
due to their ability to donate electrons
Down the group, how does the reducing power of group 2 change and why?
more powerful reducing agents:
* more shells * greater shielding effect * weaker electrostatic attraction of outer electrons * electrons lost/donated more easily
What are the redox reactions of group 2?
+ O2 ⟶ metal oxide
+ H2O ⟶ metal hydroxide + H2
+ (dilute) ACID ⟶ salt + H2
metal + oxygen ⟶
metal oxide
metal + water ⟶
metal hydroxide + hydrogen
metal + dilute acid ⟶
salt + hydrogen
Down the group, how does ionisation energy, reactivity, and reducing power of group 2 metals change?
ionisation energy less endothermic - greater shielding
reactivity ↑ - electrons lost more easily
reducing power ↑ - these electrons are donated
Explain how the solubility of metal hydroxides changes down the group:
Solubility ↑ down group:
* more shells * larger atomic radius * weaker electrostatic attraction between oppositely charged ions * less energy required to break ionic bonds
Explain how the pH of hydroxides changes down the group:
pH ↑ down group:
* Solubility ↑ * concentration of OH ↑
Metal hydroxides with a higher _____ form more alkaline solutions.
solubility
How do you test the solubility of metal hydroxides?
- mix group 2 hydroxide + water
- shake
- measure pH using universal indicator
- repeat using different metal hydroxides
What are the uses of group 2 metal hydroxides?
INCREASE pH OF ACIDIC SOIL
ANTACIDS
How can group 2 metal hydroxides be used to increase the pH of soil?
Ca(OH)2 added
neutralises acids by reacting with H+