Chapter 24 Key Concepts Flashcards
Properties of the d block elements
catalysts
color change
uses of Ag Ni Cu Zn
coinage
uses of iron
construction
making tools
uses of copper
electric cables
water pipes
uses of Ti
aerospace
joint replacement
cosmetic dentistry
what are the two strange d block elements and what is so strange about them
Chromium
-should be 3d4 4s2 but it is 3d5 4s1. this is for added stability the half filled d5 shell brings
Copper
- should be 3d9 4s2 but it is 3d10 4s1. this is for added stability that a fully filled d10 sub shell brings
what two d block elements are, by definition NOT transition elements
Scandium
-only makes Sc 3+. the highest energy level is 3p. d orbital is empty
Zinc
-only makes Zn2+. highest energy level is 3d10. not a partially filled d orbital.
characteristics of a transition elements that sets them apart from other entals
form colored compounds
their elements and compounds can act as catalysts
they form compounds where the transition element has different ox states
Ti oxidation state and colour
2
3 pink
4
5
V oxidation state and colour
2 pink
3 green
4 blue
5 yellow
Cr oxidation state and colour
2 blue 3 green 4 5 6 orange
Mn oxidation state and colour
2 pink 3 4 mauve 5 6 green 7 violet
Fe oxidation state and colour
2 pale green 3 pale yellow 4 5 6
Co oxidation state and colour
2 pink
3 green
4
5
Ni oxidation state and colour
2 green
3
4
Cu oxidation state and colour
1
2 blue
3
what’s the color of K2Cr207
bright orange
color of Nickle 2 sulfate?
green
color of hydrated copper sulfate?
blue
whats the transition metal catalyst in the Haber process?
Fe
whats the transition metal catalyst in the contact process?
Valadium as Valadium trioxide
whats the transition metal catalyst in the hydrogenation of vegetable fats to make margarine?
ni
whats the transition metal catalyst in the catalytic decomposition of hydrogen peroxide?
Manganese as Mn02
whats the aq transition metal catalyst in the reaction of Zn with acids
Cu2+ aq
whats the aq transition metal catalyst in the reaction iodide ions and peroxodisulphate iond S2082-
Fe2+ aq
how is a complex ions formed
when one or more molecules or negatively charged ions bind to a central mental ion to make a coordinate bond
what color is [Cr(H20)6]3+
blue
what color is [Cu(H20)6]2+
blue
examples of monodentate ligands
H20 NH3 Cl- CN- OH-
examples of bidentate ligands
1,2-diamoethane (em) ethandioate ion (oxalate ion) 2-
shape when 6 coordinate complexes?
octahedral . bond angle around the central metal ion is 90 degrees.
eg MnSo4 dissolved in water making [Mn(H206)]2+
eg. [Co(H2NCH2CH2NH2)
shape when 4 coordinate complexes?
Tetrahedral
more common. 109.5. eg [Cu(Cl4)]2- (yellow) and [Co(Cl4)]2- (blue)
or square planar
only in complex ions of transition metals with 8 d electrons in the highest energy d sub-shell. eg Platinum 2+ Palladium 2+ Gold 3+.
eg.
[Pt(NH3)4]2+. 90 degrees
Two types of steoisomerism that transition metals can show
cis trans
optical
cis trans occurs in…
-some square planar with no more than 2 identical ligands attached to the central metal ion eg [Pd(NH3)2Cl2]
-octahedral complex ions
monodentate 4 or 2 of the other [Co(NH3)4Cl2]2+
bidentate [Co(en)2Cl2]+
cis trans AND optical occur in …
some octahedrals containing two or more bidentate ligands
angle of the identical ligands in the trans isomenr
180
angle of the idential ligands in the cis isomenr
90
what happens when CO binds to haemoglobin
makes carboxyhaemoglobin. when con too high O2 transport prevented and leads to death,
ligand sub takes lace, O2 replaced by CO
CO binds more strongly than O2, so strong the process is irreversible
small CO can prevent a lot of hemoglobin molecules carrying O2
Cu ppt reaction with ammonia
1.Cu2+ + 2OH- —> Cu(OH)2 (s)
pale blue to blue ppt
2.[Cu(H20)6]2+ +4NH3–> [Cu(NH3)4(H20)2]2+ +4H20
ppt distolves in excess ammoniua to make to dark blue solution
Cr ppt reaction with ammonia
1.Cr3+ + 2OH- —> Cr(OH)3 (s)
violet to grey-green ppt
2.[Cr(H20)6]3+ +6NH3–> [Cr(NH3)6]3+ +6H20
green ppt distolves in excess ammoniua to make to dark purple solution
Fe 2+ ppt reaction with ammonia
Fe2+ + 2OH- ---> Fe(OH)2 (s) pale green to green ppt. in air Fe(OH)2 ---> Fe(OH)3 orange brown ppt no further reaction with NH3 as these ppt don't dissolve
Fe 3+ ppt reaction with ammonia
Fe3+ + 2OH- —> Fe(OH)3 (s)
pale yellow to orange-brown ppt
no further reaction with NH3 as these ppt dont dissolve
Mn ppt reaction with ammonia
Mn2+ + 2OH- —> Mn(OH)2 (s)
pale pink to light brown ppt
no further reaction with NH3 as these ppt dont dissolve
Cu ppt reaction with aq NaOH
1.Cu2+ + 2OH- —> Cu(OH)2 (s)
pale blue to blue ppt
ppt is insoluble in excess NaOH
Fe 2+ ppt reaction with aq NaOH
Fe2+ + 2OH- ---> Fe(OH)2 (s) pale green to green ppt. in air Fe(OH)2 ---> Fe(OH)3 orange brown ppt
ppt is insoluble in excess NaOH
Fe 3+ ppt reaction with aq NaOH
Fe3+ + 2OH- —> Fe(OH)3 (s)
pale yellow to orange-brown ppt
ppt is insoluble in excess NaOH
Mn ppt reaction with aq NaOH
Mn2+ + 2OH- —> Mn(OH)2 (s)
pink to light brown ppt
ppt is insoluble in excess NaOH
Identifying Carbonate ions
add dilute HNO3 (aq) look for effervescence
H+(aq) + CO32-(aq) —> CO2(g) + H20(l)
eq for Ox Fe2 to Fe3
basis of a redox titration.
add MnO4- ions in acid conditions
MnO4- (aq) +5Fe2+ (aq) +8H+(aq) => Mn2+ (aq) + 2Fe3+ (aq) + 7H20(l)
purple to colourless
eq for Red of Fe3 to Fe2
2Fe3+ (aq) + 2I-(aq) –> 2Fe2+(aq) + I2(aq)
orange brown pale green brown
-colour change obscured by the ox of Iodide ions to make Iodine
eq for dicromate (VI) to Cr3+
3Zn(s) +Cr2O72- (aq) +14H+(aq) => 3Zn2+ (aq) + 7H20 + 2Cr3+ (aq)
orange to green
what do you get when you add hot alkaline hydrogen peroxide to Cr3+ aq? write the full eq
Oxidation of Cr3+ to Cr042-
10OH- + 4H202 + 2Cr3+ => 2Cr042- +8H20
*H202 is a a very strong ox agent
what do you get when yu react hot dilute H2SO4 with Cu2O?
water, blue solution of CuSO4 and brown ppt of Cu
aq Cu2+ reacts with excess iodide ions. what do you get? and what is the eq
reduction of Cu2+ to Cu+.
2Cu2+ (aq) + 4I(aq) –> 2CuI(aq) + I2(s)
pale blue white ppt brown
write the further reduction of Cr3+ to Cr2+ in excess Zn
zn(s) +2Cr3+ (aq) => Zn2+ (aq) + 2Cr2+ (aq)
green pale blue
what does a more positve e mean?
E value more positve
Eq more likely to gain electrons shift right and undergo reduction
what does a more neg e mean?
E value more neg
Eq more likely to lose electrons shift left and undergo oxidation
what does a more positive e mean?
E value more positive
Eq more likely to gain electrons shift right and undergo reduction
[Cu(H2O)2(NH3)4]2+
Deep blue
[Co(NH3)6]2+
Brown yellow solution
[CuCl4]2-
Yellow
[CoCl4]2-
Blue solution
