Topic 4a - Groups 1&2 Flashcards
What is the trend in melting/boiling point going down groups 1&2 and why?
It decreases because the strength of the metallic bonding is weaker as the radius of the cation increases, so the forces between oppositely charged ions are weaker
What is the trend of density going down groups 1&2
Density increases because there is an increase in mass in the nucleus which outweighs the increase in volume
What happens to the trend in ionisation energies going down groups 1&2
Ionisation energy decreases as the increase in nuclear charge is outweighed by the increase in distance between the outer electron and the nucleus, and the increase in the shielding effect by other full shells of electrons
What is the colour of the flame test for the strontium ion (Sr2+)?
Crimson red
How does ionisation energies change from group 1 to group 2
Across a period I.E. increase because nuclear charge increases, the distance of the outer electron from the nucleus decreases and the shielding effect stays similar
How does the solubility of group 1&2 element in sulfates change going down the group
The solubility decreases
How does the solubility of hydroxides change going down groups 1&2
It increases
Which are more soluble in hydroxides (OH)2 and sulfates SO4, group 1 or group 2
Group 1 salts are more soluble than their group 2 equivalents
What determines solubility
If the exothermic reaction is bigger than the endothermic reaction
How does the thermal stability of carbonates and nitrates change going down groups 1&2
They increase due to polarising power of the cation decreasing (radius increases, charge is the same)
Which is the only ion from group 1 that can polarise the carbonate ion
Lithium ion because it has a similar charge density and therefore polarising power to Mg2+
