Group 2 Flashcards
Outline the trend in Gp2 for atomic radius
Increases down the group (more shell and shield)
Outline the trend in ionisation energy in gp2
Decrease down the group
More shells and shielding = less attraction -> less IE
Outline the trend in melting points
Decrease down the group
Hi ionic radius so less e- attraction of ions and sea of e- so weak metal bonds
Rank the gp2 hydroxides for solubility (descending order)
Ba(OH)2
Sr(OH)2
Ca(OH)2
Mg(OH)2
Rank the Gp2 sulfates solubility (in descending order)
MgSO4
CaSO4
SrSO4
BaSO4
Outline the reaction of Mg with steam & outline why MgO forms & not Mg(OH)2
Mg(s) + H2O (g) -> MgO(s) + H2(g)
Mg(OH)2 decomposes in heat
Outline the 3 reaction observations & their reasons
- Gas produced burns = H2 flammable
- Mg burns bright = Exothermic
- White (s) produced = MgO
Outline the reaction of Ca with H2O & conditions
Ca(s) +2H2O (l) -> Ca(OH)2 (s) +H2 (g)
H2O is cold
Outline the 3 observations and reasons for Ca and H2O
- Gas pops with lit splint= Flammable H2O
- Flask hot = Exothermic
- White ppt = Ca(OH)2 not that soluble
- pH 12 = Alkaline
Outline the reaction of Sr and H2O
Sr(s) + H2O(l) -> Sr(OH)2 (aq) + H2(g)
Outline the observations for SO4^2- ions
White ppt - BaSO4
H2O & CO2 as bi-productsO
Outline the reagent for SO4^2- test and give a reason as to why
Acidified BaCl2 - to react with CO3^2- ions to prevent reaction
Outline the observations for Ba^2+ ions
White ppt - BaSO4
H2O & CO2 as bi products
Outline the reagent for Ba2+ test
Na2SO4 solution
Outline the observations for the test for OH- ions
White ppt Mg(OH)2
Outline the reagent for the OH^- test
MgCl2
Outline the observation for the Mg2+ ions test
White ppt Mg(OH)2
Outline the reagent for the Mg2+ test
NaOH (aq)
Outline the observation for the Cl- ion test
White ppt (AgCl2)
Outline the reagent for the Cl- ion test and outline why
AgNO3 (acidified) = acid HNO3 to prevent CO3^2- &/or OH- reactingO
Outline the observation of the CO3^2- test
Effervescence (bubble thru limewater = milky)
Outline the reagent for the CO3^2- test and outline why
HNO3 - all nitrates are soluble
Outline the use of Mg(OH)2 in medicine
Antacid - neutralises excess stomach acid
Outline the use of Ca(OH)2 in agriculture
Reduces soil acidity & gives Ca2+ ions for growth
Outline the use of CaO/CaCO3 to remove SO2 frrom flue gas
Prevents acid rain
1. CaO(s) + SO2(g) -> CaSO3(s)
2. CaCO3(s) + SO2 -> CaSO3(s) + CO2(g)
Outline the use of BaSO4 in Medicine
‘Ba meal’ outline gut as x-rays can’t pass (toxic but insoluble so :) )
Outline the reaction of Mg for Ti extraction from TiCl4 (Symbol & half)
TiCl4 + 2Mg -> 2MgCl2 + Ti
Mg -> Mg2+ + 2e-
(Mg oxidised & more reactive than Ti)
Outline how TiCl4 is formed for extraction
TiO2 + 2C + 2Cl2 -> TiCl4 + 2CO
