Group 2 Flashcards
describe the trend in solubility of group 2 metal hydroxides down the group (1)
solubility of metal hydroxides increases
what is the pH of Mg(OH)2
pH 10
what uses does mg(OH)2 have ?
neutralise stomach acid
what is the pH of Ca(OH)2
11
what uses does Ca(OH)2 have ?
neutralise acidic soil in agriculture
other than Mg(OH)2 what else can be used to neutralise stomach acid ?
CaCO3
describe the trend in pH of group 2 metal hydroxides down the group (1)
pH of metal hydroxides increases down the group (becomes more alkaline)
describe the trend in solubility for group 2 metal carbonates down the group (1)
solubility of metal carbonates decreases
state the solubility of each group 2 metal carbonate
BeCO3 - barely soluble
MgCO3 - barely soluble
CaCO3 - insoluble
SrCO3 - insoluble
BaCO3- insoluble
describe the trend in the solubility of group 2 metal sulfates (1)
solubility of metal sulfates decreases
state the solubility of each group 2 metal sulfate
BeSO4 - soluble
MgSO4 - soluble
CaSO4 - insoluble
SrSO4 - insoluble
BaSO4 - insoluble
describe the trend in reactivity down group 2 (6)
- reactivity increases down group
- greater number of electron shells
- atomic radius increases
- greater electron shielding
- weaker nuclear attraction between nucleus and outermost electron
- form cations (lose electrons) more readily
which group 2 elements will be better reducing agents ? (1)
those further down the group (form cations more readily (lose e-))
write a balanced symbol equation for the reaction between calcium (any group 2 metal) and oxygen
2Ca(s) + O2(g) = 2CO (s)
describe how beryllium reacts with water (1)
no reaction with water
describe how magnesium reacts with water (2)
- very slow reaction with water
- reacts vigorously with steam (H2O (g)) but produces Magnesium oxide
write the equation for the reaction of any group 2 metal (not beryllium or magnesium) reacting with water
Ca(s) + 2H2O(l) = Ca(OH)2 (s) + H2(g)
what observations can be made when a group 2 metal reacts with water (2)
- effervescence
- alkaline solution formed (OH-)
describe the differences in chemistry and observations between the reactions o f magnesium with water and steam (8)
- with water :
- very slow reaction
- slight effervescence produced
- magnesium hydroxide produced
- alkaline solution pH around 10 - with steam
- fast reaction
- faster effervescence produced
- magnesium oxide produced
- no alkaline solution
write the equation for the reaction of any group 2 metal with any dilute acid eg. HCl
Ca(s) + 2HCl(aq) = CaCl2 (aq) + H2(g)
which reaction can group 2 metal carbonates undergo ? (1)
thermal decomposition
what is a thermal decomposition reaction ?
- breakdown compound into 2 or more diff substances using heat
what will affect the amount of heat energy needed for a group 2 metal carbonate to undergo thermal decomposition ? (1)
- charge density
explain how charge density will affect the amount of heat energy needed for a group 2 metal carbonate to undergo thermal decomposition ? (2)
- greater charge density of metal ion = more polarised carbonate ion becomes
- greater polarisation = less heat needed to break C-O bond
describe the trend in charge density down of group 2 metal carbonates down the group (2)
- charge density decreases
- thermal stability increases (more heat needed)
what is a combination reaction ? (1)
when 2 or more compounds or elements combine to form 1
