Group 7 Flashcards
Observations
Silver nitrate + Iodine ions
Yellow precipitate forms
Observations
Silver nitrate + Flourine ions
No visible change
Observations
Silver nitrate + Chlorine ions
White precipitate forms
Observations
Silver nitrate + Bromine ions
Cream precipitate forms
Equation : solubility of silver halide + NH3
AgX (s) + 2NH3 (aq) —> Ag(NH3)2 (aq) + X- (aq)
Silver nitrate + halide ions equation
AgNO3 + NaX —> AgX +NaNO3
H2SO4 + Cl-
Acid base reaction
Misty fumes produced (HCl)
H2SO4 +Br-
Acid base and Redox reaction
Br- reduces H2SO4 to SO2
Misty fumes (HBr)
Choking gas (SO2)
Brown gas (Br2)
H2SO4 +I-
Acid base and redox
Reduces H2SO4 to SO2, S and H2S in 3 separate reactions
Misty fumes (HI)
Choking gas (SO2)
Yellow solid (S)
Black solid and purple gas (I2)
Rotten egg smell (H2S)
H2SO4 +F-
Acid base
Misty fumes (HF)
Cl2 +Br - observations
Yellow solution forms
Cl2 + I- observations
Brown solution forms
Ionic equation
overall equation
Cl2 + I-
2KI + Cl2 —> I2 + 2KCl
2I- + Cl2 —> I2 + 2Cl-
Br2 + I- observations
Brown solution forms
Overall equation
Ionic equation
Cl2 + Br-
2KBr + Cl2 —> Br2 + 2KCl
Cl2 + 2Br- —> Br2 + 2Cl-
Solubility of AgCl in NH3
Concentrated - no reaction
Dilute - soluble completely dissolves
Solubility AgI in NH3
Concentrated - insoluble no visible change
Dilute - insoluble no visible change
Solubility AgBr in NH3
Concentrated - soluble, dissolves
Dilute - sparingly soluble, partially dissolves
Oxidising ability of group 7
Oxidising ability decreases down group 7
Atomic radius increases
More shielding
Gains electron less easily
Reducing ability of group 7
Reducing ability increases down group 7
Size of ion increases
Shielding increases
Outer electron further from nucleus
Less attraction
Overall and ionic equations Cl2 + I-
2KI + Cl2 —> I2 + 2KCl
Cl2 + 2I- —> I2 + 2Cl-
Why can HCl not be used in place of NH3 (solubility of group 7)
HCl contains chloride ions which would give a false positive
