2: Group 2 Flashcards
How does atomic radius change down the group and why?
Increases
This is because the number of electron shells increases
How does 1st ionisation energy change down the group?
Decreases
Why does ionisation energy decrease down the group?
Which effect is overridden?
Atoms get an extra electron shell down the group. This increases the shielding effect. Outer electrons are further from the nucleus so attraction is reduced.
The effect of higher nuclear charge is overridden by shielding.
How does reactivity change down the group and why?
Reactivity increases as the outer electron is released more easily, due to less attraction to the nucleus. This means ionisation energy is low.
Why does melting point generally decrease down the group?
The size of the atom increases, but the number of delocalised electrons does not increase. Electrons get further from the nucleus down the group so electrostatic attraction is reduced.
Give the equation for calcium + water.
Ca(s) + 2H2O(l) -> Ca(OH)2 (aq) + H2(g)
Give the equation for magnesium + steam.
Mg(s) + H2O(g) -> MgO + H2
How does the solubility of group 2 hydroxides change down the group?
Solubility increases down the group
What colour is aqueous Mg(OH)2?
White
What colour is aqueous Ba(OH)2?
Colourless
How does solubility of group 2 sulfates change down the group?
Decreases
What colour is aqueous MgSO4?
Colourless
What colour is aqueous BaSO4?
White
What are the uses for BaSO4 in medicine?
Barium meal, helps the digestive system to become visible on xrays.
Mg can be used to extract which metal?
Titanium
