4. Inorganic Chemistry & Periodic Table Flashcards
(50 cards)
Group 2 - Atomic Radius
Atomic radius increases as you go down the group due to additional electron shell
Group 2 - Ionisation energy
Ionisation energy decreases as you go down the group due to a greater atomic radius and increased shielding, which makes it easier to lose electrons
Group 2 - Reactivity
Reactivity increases down the group as the electron shielding increases, and the atomic radius increases, so outer electrons are easier to remove
Group 2 metals reaction with water
- redox reaction
- produces a metal hydroxide and hydrogen
- metal hydroxide forms an alkaline solution
Magnesium reaction with steam
- produces magnesium oxide and hydrogen
- reaction is faster as steam provides energy
Group 2 metals reaction with chlorine
- form metal chlorides
- white precipitate forms
Group 2 metals reaction with oxygen
- produces metal oxide
- barium and strontium may react with excess oxygen to form metal peroxides
Group 2 metal reactions with dilute acids
- produces bubbles of hydrogen and solutions of metal compounds
- Hydrochloric acid: X + 2HCl –> XCl2 + H2
- Sulfuric acid: X + H2SO4 –> XSO4 + H2
- Nitric acid: X + 2HNO3 –> X(NO3)2 + H2
Reaction of group 2 metal oxides with dilute acids
Hydrochloric acid: MgO + 2HCL –> MgCl2 + H2O
Sulfuric acid: CaO + H2SO4 –> CaSO4 + H2O
Nitric acid: MgO + 2HNO3 –> Mg(NO3)2 + H2O
Reaction of group 2 metal hydroxides with dilute acids
Hydrochloric acid: Mg(OH)2 + 2HCl –> MgCl2 + 2H2O
Sulfuric acid: Ca(OH)2 + H2SO4 –> CaSO4 + 2H2O
Nitric acid: Mg(OH)2 + 2HNO3 –> Mg(NO3)2 + 2H2O
Solubility of group 2 hydroxides
Group 2 hydroxides increase in solubility, meaning magnesium hydroxide is the least soluble and barium hydroxide is the most soluble.
Uses of Magnesium Hydroxide
- Antacids in medicine as it can neutralise acids
- Used in agriculture to neutralise acidic soils
Solubility of Group 2 Sulfates
Group 2 sulfates decrease in solubility as you go down the group, meaning magnesium sulfate is the most soluble, and barium sulfate is the least soluble.
Use of Barium sulfate
The insolubility of barium sulfate means it is useful in medicine as barium meals. These are a form of medical tracers that allow internal tissues and muscles to be imaged
Thermal decomposition of Group 1 Carbonates
- They are all thermally stable, meaning they won’t decompose
- Exception is Lithium carbonate, which decomposes to form lithium oxide and carbon dioxide
Li2CO3 –> Li2O + CO2
Thermal decomposition of Group 1 nitrates
- Group 1 nitrates decompose to form metal nitrates and oxygen
2NaNO3 –> 2NaNO2 + O2 - Exception is Lithium nitrate, which decomposes to form lithium oxide, nitrogen dioxide, and oxygen
4LiNO3 –> 2Li2O + 4NO2 + 2O2
Thermal decomposition of Group 2 Carbonates
- Decompose to form metal oxides and carbon dioxide
CaCO3 –> CaO + CO2
Thermal decomposition of Group 2 Nitrates
- Decompose to form metal oxides, nitrogen dioxide, and oxygen
2Ca(NO3)2 –> 2CaO + 4NO2 + O2
Thermal stability of group 1 and 2 carbonates and nitrates
Thermal stability of carbonates and nitrates increase as you go down the groups
How does Cation Size affect thermal stability?
As we move down the group, cations become larger.
Larger cations have low charge density.
This results in lower polarising power, causing less anion distortion.
Less distortion leads to strong C-O and N-O bonds, increasing stability
How does Cation Charge affect thermal stability?
Group 2 cations (2+) have a higher charge density than group 1 cations (1+)
Higher charge density results in greater polarising power
This makes group 2 compounds less stable than group 1 compounds
Flame colour for Lithium
Red
Flame colour for Sodium
Orange/Yellow
Flame colour for Potassium
Lilac
