Topic 4 - inorganics Flashcards
How does ionisation energy change down group 2?
Decreases as more shielding
How does group 2 from Be - SR react with oxygen?
All burn vigorously except Be. 2M + O2 –> 2MO
How does Barium react with oxygen?
Vigorously. Ba + O2 –> 2BaO2
What is the trend on reactions of group II with water? and comparison to group 1?
Group 2 less reactive than comparative group 1. Increases in vigour down the group.
What is the equation for Mg and water?
Mg + H2O –> MgO + H2
What is the equation for Ca, Sr or Ba in water?
M + 2H2O –> M(OH)2 + H2
Explain water happens with Be and water?
Beryllium doesn’t react with water
What is the equation for group II and chlorine?
M + Cl2 –> MCl2
How do group II oxides react with water?
Form M(OH)2 except BeO
How do group II oxides react with dilute acids?
Forms salt and water
Why do group II hydroxides react with acids?
They are bases
How does group II sulphates solubility change?
Less soluble down the group.
How does group II hydroxides solubility change?
More soluble down group. All partially soluble
What changes the thermal stability of carbonates?
More stable = stronger CO bond = anion polarised less = large cation = more stable down group
How does thermal stability of group 1 carbonates change?
Li not stable under bunsen heat(Li2CO3 –> Li2O + CO2). All others are increasingly more stable
How does thermal stability of group 2 carbonates change?
More stable down group but, all decompose under heat to form MCO3 –> MO + CO2
How does group II thermal stability of nitrates change down group?
More stable down group. Forms 2MO + 4NO2 + O2
How does group 1 thermal stability of nitrates change?
More stable down group. All decompose (except Li) to MNO2 + O2. Lithium forms Li2O + NO2 + O2
What are the flame tests of group 1 and II?
LI+ - Red. Na+ - yellow. K+ - Lilac. Ca2+ - Brick red. Sr2+ - Crimson. Ba2+ - Apple green
What is chlorine’s appearance at rtp, in aq solution and hydrocarbon solution?
Green gas at rtp. Pale green in solutions.
What is Bromine’s appearance at rtp, in aq solution and hydrocarbon solution?
Red/Brown liquid at rtp. Orange/Yellow in aq. Red in hydrocarbon solution.
What is Iodine’s appearance at rtp, in aq solution and hydrocarbon solution?
Grey/black solid at rtp. Brown in aq. Violet in hydrocarbon solution.
How does electronegativity change down group 7?
Decreases down the group as bigger element less electronegative.
How does mtp change for group 7?
Increases down group as more London forces.
What is noticeable about group 7 reactions with metals and non-metals?
More exothermic up the group with metals. More explosive up group with non-metals. E.g. Chlorine + H2 exlplode in sunlight, bromine needs catalyst and Iodine is very slow.
How do group 7 act as oxidising agents?
Stronger oxidising agents up group as gain e- more easily.
How do group 7’s reactions with conc. H2SO4 change?
Better reducing agents down group as lose electron more easily. Meaning HI and HBr form I2 and Br2 but KCl only forms HCl
How do you test for a halide?
Add nitric acid and silver nitrate. Cl- forms white ppt. Br- cream and I- yellow.
How can you test halide ppts after silver nitrate test?
Add ammonia solution, AgCl dissolves, AgBr only in conc. and AgI doesn’t.
Are hydrogen halides soluble?
Yes, in water for acids.
Why don’t we use Astatine?
It is radioactive
Test for carbonate ion?
Add dilute acid, test gas with limewater. Goes cloudy as CO2 produced.
Test for sulfate ion?
Add dilute HCl to solution followed by Barium Chloride. Forms white ppt.
Test for Ammonium ion?
Warm with NaOH. Hold damp red litmus. Ammonia gas turns it blue
