group 2 Flashcards
the trends in atomic radius of elemnets Mg-Ba
atomic radius increases down the group due to increased sheilding
the trends in first ionisation energies of elemnets Mg-Ba
decreases down group due to greater atomic radius and increased shielding
the trends in melting point of elemnets Mg-Ba
decreases down the group as group 2 are metallic so larger the ions within the metallic structure the weaker the attractive forces, as have to act over larger distance
the trends in reactivity of elemnets Mg-Ba
increase down the group as increased shielding makes the outer electrons easier to lose
reaction of group 2 elements with water
metal + water –> metal hydroxide + hydrogen
magnesiums reaction with water and its solution
reacts very slowly with liquids water to form Mg(OH)2
however much faster with steam as provided reaction with more energy, reacts to form MgO(a white powder) and H2
use of magensium in the extraction of titainum from TiCl4
via displacement reaction
TiCl4 + 2Mg –> 2MgCl2 + Ti
relative solubilities of group 2 hyrdoxides
Mg(OH)2 is sparingly soluble
increases down the group
relative solubilities of group 2 sulphates
BaSO4 is insoluble
decreses down group 2
use of Mg(OH)2 in medicine
antacid as it is alkaline, neutralises stomach acid
use of Ca(OH)2 in argiculture
nuetralise acidic soils
use of CaO or CaCO3 to remove SO2 from flue gases
CaO + 2H2O + SO2 –> CaSO3 + 2H2O
calcium oxide reacts with Sulphur dioxide from factory pollutants and prevents it being released into atmosphere
test for sulphate ions
add BaCl2
if sulphate ions present white precipitate forms
Ba2+ + SO4 2- –> BaSO4
use of BaSO4 in medicine
very good for absorbing x-rays so digestive system can be imaged by feeding a patient a barium meal, highly toxic but as insoluble it cannot dissolve of pass through cell membrane into body tissue so perfectly safe
