Group 2 Flashcards
What is metallic radius
Half the distance between nuclei in a giant metallic lattice
Describe and explain the trend in IE down group 2
IE decreases
Nuclear charge increase outweighed by sheilding effect
And distance from valence shell increasing
Describe the trend in reactivity of group 2
Reactivity increases
Ability to lose e- increases
Why are cations of group 2 smaller in radius than their atoms
Cations have one less shell
Less electrons less repulsion
Describe the trend in reducing power down group 2
Increases
Describe and explain the trend in melting points down group 1 and 2
Decreases
Size of atom increases
Decrease in metallic bond strength
Write an equation for the reaction of group 2 metals with H2O
X + H2O—-> X(OH)2 + H2
Describe observations of reaction of group 2 metals with water down the group
Reaction vigour increases down group-effervescence of H2 gas increases
Solubility of hydroxides formed increases thus pH increases more alkaline solution formed
Describe and explain the trend in solubilities of sulfates down group 2
Solubility decreases BeSO4 (aq) MgSO4 (aq) CaSO4 (s) SrSO4(s) BaSO4 (s)
Radius of cation increases charge density decreases
Lattice energy decreases
Enthalpy of hydration decreases
Decrease in enthalpy of hydration is greater
Thus enthalpy of solution becomes more endothermic
Describe and explain the trend in solubility of group 2 hydroxides and oxides
Increases down group
Be(OH)2 / Mg(OH)2 (s) insoluble
Ca(OH)2 (aq) partially soluble
Sr(OH)2/Ba(OH)2 (aq) very soluble
Both L.E and ΔHhyd decrease
Decrease in LE is greater than hydration
Enthalpy of solution becomes more exothermic
Write equation for reaction of group 2 metals with oxygen
X + 1/2O2 —–> XO
Observations when Be reacts with oxygen
Silver grey solid dissappears
White solid forms
Bright White flame
Observations when Mg reacts with oxygen
Silvery grey solid dissapears
White solid formed
Burns in white flame
Observations when Ca reacts with oxygen
Silvery grey solid dissappears
White solid formed
Burns in a brick red flame
Observations when Sr reacts with oxygen
Silvery grey solid dissappears
White solid appears
Burns in scarlett/crimson red flame
Observations when Ba reacts with oxygen
Silvery grey solid dissappears
White solid appears
Burns in apple green flame
Write equation for reaction of oxides and hydroxides with dilute acid
Basic oxide/ hydroxide + dilute acid—> salt + water
Write equation for reaction of a group 2 metal with dilute acid
Metal + dilute acid —-> salt + H2
Write equation for reaction of group 2 carbonates with dilute acid
Carbonate + dilute acid —-> salt + CO2 + H2O
CO2 turns limewater milky
Reaction of group 2 carbonates with water
INSOLUBLE
What carbonates are soluble in water
Group 1 and ammonium carbonates are soluble
Reaction of BeO with water
No reaction insoluble
Reaction of MgO with water
MgO+ H2O—> Mg(OH)2 (aq) very slightly soluble
CaO + H2O —> Ca(OH)2 (aq)
SrO + H2O—-> Sr(OH)2 (aq)
BaO + H2O —–> Ba(OH)2 (aq)
Write equation for thermal decomposition of group 2 carbonates
XCO3 (s)—-> XO(s) + CO2 (g)
Describe and explain trend in thernal stabilities of group 2 carbonates and nitrates
Thermal stability increases
Down the group charge density of cation decreases
Ability of cation to polarize anion decreases
Bonds get less polarized
More heat required down the group
(thermal decomposition becomes more endothermic)
Write equation for thermal decomposition of nitrates
X(NO3)2 —-> XO (s) + 2NO2(g) + 1/2O2 (g)
Observation of decomposition of nitrates
Brown NO2 gas
Write equation for thermal.decomposition of group 2 hydroxides
X(OH)2 —-> XO (s) + H2O (g)
Uses of MgO
Refractory material in lining of furnaces
Uses of Mg(OH)2
Antacid tablets
Uses of CaO( quick lime) and Ca(OH)2
Used to treat acidic soils and for flue gas desulfurization
/ USED TO RAISE PH
Uses of CaCO3 (limestone)
Building material
Uses of BaSO4
Ba meal for x rays
