Group Two, The Alkaline Earth Metals Flashcards
trend in first ionization energy
decreases down the group. more shielding so less attraction between the nucleus and outer most electrons,so less energy needed to remove one.
trend in atomic radius
increases down the group as there are more electron shells
trend in melting point
in general, melting point decreases. as ions get bigger, there is a weaker magnetic force. the slight differences in the way the ions stack up cause a slight wobble
reaction of Mg with water
no reaction with cold water, combustion reaction with steam. Mg + H2O -> MgO + H2
reaction of Ca with water
fizzes and after time forms a white solid Ca + 2H2O -> Ca(OH)2 + H2
reaction of Sr and Ba withwater
Fizzes and forms a colorless solution (same formula as Ca)
trend in reactivity
reactivity increases down the group. There are more electron shells. the outer electrons are easier to remove as they are further away from the nucleus and there is more shielding resulting in a lower nuclear attraction.
metal+ acid
salt + H2
trend in solubility
as we go down group two, the solubility of sulfates formed decreases
use of Mg(OH)2
a hydroxide. used to neutralize stomach acid as it is insoluble (wont make an alkaline)
what is Mg used for
to extract titanium from the ore (Ti)2)
TiO2+2C+2Cl2 -> TiCl4 +2CO
TiCl4 + 2Mg -> Ti + 2MgCl2
problem: Mg has to be extracted
use of Ca(OH)2
neutralize acidic soil - slaked lime
use of CaO or CaCO3
flue gas desulfurisation. sparingly 4. CaO+SO2
use of acidified BaCl2
Acidified to remove carbonate ions. BaCl4 is used in a displacement reaction to test for sulfate ions where a solid forms.
use of BaSO4
insoluble. x-rays can’t pass through, barium meal consumed to check the digestive system
