Group 2 Flashcards
What is the trend in the melting points down the group?
Explain it
Decreases down group
Group 2 are metallic structures
They all have 2 delocalized electrons which doesn’t change
The atomic radius decreases down the group
So delocalized electrons are further from positive nucleus
So less energy is needed to break the bonds
What is the equation for the reaction of water?
One of the products is dangerous. Why?
Ca + 2 H2O > Ca(OH)2 + H2
Hydrogen gas is flammable
What atom desists from the trend in melting points?
Does it have a higher or lower melting point than calcium?
Magnesium
Lower melting point
What is the trend in solubility of group 2 hydroxides?
What is the trend in solubility of group 2 sulphates?
Hydroxides - solubility increases down group
Sulphates - solubility decreases down group
What is the test for sulphate ions?
Sample + HCl + BaCl2
Is sulphate present, white precipitate (BaSO4) forms because BaSO4 is insoluble in water
What is the trend in electronegativity?
Explain
Decreases down group
Outer electrons are further out and more shielded
Why is BaSO4 useful in medicine?
Describe the process
Why is it not poisonous?
Why can’t other Ba compounds be used?
Barium meals
Meal swallowed and BaSO4 coats tissue becoming visible on X-Ray
It is insoluble
They’re poisonous because they are soluble
Describe the process of extraction of titanium
What does magnesium act as
In what temperature does the extraction of Ti from TiCl4 occur at?
TiO2 + 2 C + 2Cl2 > TiCl4 + 2CO
Heat
TiCl4 purifies via frac distillation
TiCl4 + 2 Mg > Ti + 2 MgCl2
Mg is a reducing agent, reducing Ti in 1000 degrees Celsius furnace
Why is titanium advantageous?
Strong and resistance to corrosion
Can be used to make artificial joints
How is SO2 removed from flue gases?
What are the equations?
What is the product of both of the equations?
Via wet scrubbing (reacting with alkali)
CaO + CaCO3 + H2O forms slurry for this. Slurry is sprayed on flue gases
CaO + 2H2O + SO2 > CaSO3 + 2 H2O
CaCO3 + 2H2O + SO2 > CaSO3 + 2H2O +CO2
Calcium sulphide
What is the use of Ca(OH)2 in agriculture?
What is the use of Mg(OH)2?
What is an antacid?
To neutralize acidic soils
ndigestion tablets as an antacid
Substance that neutralizes excess stomach acid
What is the trend in reactivity down group 2?
Explain it
It gets more reactive down the group
Because the larger the atom, the further away the outer electrons are from the positive nucleus and the more shielded
Ionization energy decreases
So easier it is to lose an electron
So it is more reactive
