topic 4 Flashcards
What is a common name given to group 2 metals?
Alkaline earth metals
What is the most reactive metal of Group 2?
Barium
List 3 physical properties of group 2 metals?
High melting and boiling points
Low density metals
Form white compounds
The highest energy electrons of Group 2 metals are in which subshell?
S subshell
What is the trend in reactivity down group 2? Why is it this way?
it increases down the group
Electrons are lost more easily due to larger atomic radius and increased shielding
What is the trend in ionisation energy down group 2? Why is it this way?
it decreases
increased number of shells, so more shielding
increased atomic radius, so weaker forces of attraction to nucleus
so less energy is needed to remove electron
What type of reaction is the reaction between group 2 elements and oxygen?
redox reaction
What are the products when group 2 elements react with water?
hydroxide (OH-)
hydrogen gas (H2)
Which group 2 element does not react with water?
Beryllium
Which group 2 element reacts very slowly with water?
magnesium
What type of reaction is the reaction between group 2 metals and water?
Redox reaction
What are the products when a group 2 oxide reacts with a dilute acid?
- salt
- water
What is formed when group 2 oxides react with water?
metal hydroxide
What is the trend in hydroxide solubility down group 2?
increases down the group
Mg(OH)2 is slightly soluble
Ba(OH)2 creates a strong alkaline solution
Which group 2 metal oxide is insoluble in water?
Beryllium oxide
what is the trend of sulfate solubility down group 2
become less soluble down the group
What is the reasoning behind the trend in thermal stability for Group 1 carbonates and nitrates?
they do not decompose except for lithium
they dont have big enough charge densities to polarise the carbonate ion as they only form 1+ ions
lithium ion is just small enough to have the polarising effect so it can decompose
What is the reasoning behind the trend in thermal stability for Group 2 carbonates and nitrates?
more thermally stable as you go down the group
cations get bigger so have less of a polarising effect (distort the carbonate/nitrate ion less)
C-O/N-O bond not weakened as much and therefore it is harder to break down
List the flame colours for the group 1 elements?
Lithium = red
Sodium = orange/yellow
Potassium = lilac
Rubidium = red
Caesium = blue
List the flame colours for Group 2 elements?
Magnesium = no colour
Calcium = brick red
Strontium = crimson red
Barium = pale green
How do you carry out a flame test?
1) Nichrome wire
2) Sterilise it by dipping the into conc. HCl and then heating it in the Bunsen flame
3) Dip wire into solid and put in Bunsen flame and observe the flame