Group 2 Flashcards
What is the trend in atomic radius in Group 2 elements?
Increases
More electron shells
So bigger atoms
What do the trend down the group of 1st ionisation energy in group 2?
Decrease.
Atoms get bigger
More shielding
Therefore weaker attraction from the nucleus to electron in outer shell
Trend in melting point in group 2
Decreases
Weaker metallic bonding
As metal ions are bigger
So lower melting points
What happens to group 2 metals when they burn in oxygen?
They burn and form metal oxides
For example, magnesium burns with a bright white flame to form magnesium oxide (MgO)
What is the chemical equation for the reaction of magnesium with oxygen?
2Mg + O2 → 2MgO
This reaction produces magnesium oxide, a white solid.
What is the melting point characteristic of magnesium oxide?
High melting point due to ionic bonding
MgO is an ionic compound formed from magnesium and oxygen.
How does the reactivity of group 2 metals change down the group?
Reactivity increases down the group
What happens to magnesium ribbon when it reacts with oxygen?
It forms a thin layer of magnesium oxide
This layer needs to be cleaned off before further reactions.
What effect does an un-cleaned Mg ribbon have on reaction rate tests with acid?
It gives a false result due to different reaction rates of Mg and MgO
What is the reaction equation for magnesium reacting with hydrochloric acid?
Mg + 2HCl → MgCl2 + H2
What is the reaction equation for magnesium oxide reacting with hydrochloric acid?
MgO + 2HCl → MgCl2 + H2O
What is the difference between magnesium’s reaction with steam and warm water?
Steam produces magnesium oxide and hydrogen with a flame; warm water produces magnesium hydroxide without a flame
What is the equation for magnesium reacting with steam?
Mg (s) + H2O (g) → MgO (s) + H2 (g)
What is the equation for magnesium reacting with warm water?
Mg + 2 H2O → Mg(OH)2 + H2
How do the other group 2 metals react with cold water?
They react with increasing vigour down the group to form hydroxides
What is the reaction equation for calcium reacting with cold water?
Ca + 2H2O (l) → Ca(OH)2 (aq) + H2 (g)
What is the reaction equation for strontium reacting with cold water?
Sr + 2 H2O (l) → Sr(OH)2 (aq) + H2 (g)
What is the reaction equation for barium reacting with cold water?
Ba + 2 H2O (l) → Ba(OH)2 (aq) + H2 (g)
What effect do the hydroxides produced from group 2 metal reactions have on water?
They make the water alkaline if they are soluble
What observable effects occur during the reaction of group 2 metals with water?
- Fizzing
- Metal dissolving
- Solution heating up
- White precipitate appearing (with calcium)
True or False: Magnesium reacts with warm water more vigorously than with steam.
False
What are the key properties of titanium that make it useful?
Abundant, low density, corrosion resistant
Titanium is used for making strong, light alloys, particularly in aircraft.