Group 2 Flashcards
How does atomic radius change as you go down group two and why
Atomic radius increases down the group
As one goes down the group, the atoms have more shells of electrons making the atom bigger
How does melting point change as you go down group 2 and why
Melting points decrease down the group.
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
How does 1st ionisation energy change as you go down group 2
Ionisation energy decreases as you go down
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.
Describe magnesium reaction with oxygen
Mg burns with a bright white flame.
The MgO appears as a white powder. 2Mg+O2 —> 2MgO
Does MgO have a high melting point or low
High
Describe the reaction between a magnesium ribbon with acid and an uncleaned magnesium ribbon with acid
Mg+2HCl—>MgCl2 +H2
MgO+2HCl—> MgCl2 +H2O
Describe how Magnesium reacts with steam
Magnesium reacts in steam to produce magnesium oxide and hydrogen.
The Mg would burn with a bright white flame.
The MgO appears as a white powder.
Mg(s) + H2O(g) MgO(s) + H2(g)
Describe how magnesium reacts with warm water
Mg will also react with warm water, giving a different magnesium hydroxide product.
Mg+2H2O —> Mg(OH)2 +H2
This is a much slower reaction than the reaction with steam and there is no flame.
What are the group two reactions with water
The other group 2 metals will react with cold water with increasing vigour down the group to form hydroxides.
Ca + 2 H2O (l)—>Ca(OH)2 (aq) + H2 (g)
Sr + 2 H2O (l)—>Sr(OH)2 (aq) + H2 (g)
Ba + 2 H2O (l)—>Ba(OH)2 (aq) + H2 (g)
What are the group two reactions with water
The other group 2 metals will react with cold water with increasing vigour down the group to form hydroxides.
Ca + 2 H2O (l)—>Ca(OH)2 (aq) + H2 (g)
Sr + 2 H2O (l)—>Sr(OH)2 (aq) + H2 (g)
Ba + 2 H2O (l)—>Ba(OH)2 (aq) + H2 (g)
What can you observe with the group two reactions with water
- Fizzing , (more vigorous down group)
-The metal dissolving, (faster down group)
-The solution heating up (more down group)
with calcium a white precipitate appearing
What is the process for extracting titanium using magnesium
TiO2 is converted to TiCl4
The TiCl4 is purified by fractional distillation in argon atmosphere
The Ti is extracted by Mg in an argon atmosphere
What are the equations for extracting titanium
TiO2 + 2Cl2 + 2C —> TiCl4 + 2CO
TiCl4 + 2Mg —> Ti + 2MgCl2
Why is titanium expensive
The cost of magnesium is expensive
It’s a batch process making it more expensive because the process is slower and requires more labour and energy
The process is also expensive due to the argon
High temperatures required in both steps
What are some of the uses of CaO
Can be used to remove SO2 from waste gases from furnaces by flue gas desulfurisation
Gases pass through scrubber contain CaO which reacts with acidic sulfur dioxide
SO2 + CaO —> CaSO3
