transition elements Flashcards
define a d block element (1)
- an element with an outer electron in a d orbital
define the term transition element (1)
an element that has an ion with an incomplete d sub shell
give the symbols of all element in period 4 that are d block elements but not transition elements (1)
- Zn and Sc
explain wether or not cadmium is a trnasition element (1)
- it is not a transition element because its ion has a full d sub shell
what is a catalyst (3)
- a substance that increase the rate of the reaction without getting used up
- by providing an alternative reactionn pathway
- with a lower activation energy
hydrogen peroxide decmplposes as follows
2H2O2 (aq) ->2H2O (l) + O2(g)
a catalyst for this reaaction is black solid manganese (IV) oxide MnO2
design an experiment that shows manganese (IV) oxide is a catalyst for this reaction (4)
- measure some hydrogen peroxide solution into a flask with a side arm connect a gas syring and start a clock measuring the gas produced in a certain time
- repeat an identical experiment but add a weighed amoutn of MnO2
- with the MNO2 the volume of gas produced is more in the same time
- filter after the second experiment and collect and dry the residue reweighing to show the catalyst has not been used up
what statements are correct
transition elements and their irons can act as catalyst because
1. they are very unreactive so they do not get used up in reactions
2. they readily undergo redox reactions
3. they have variable oxidation states (1)
2 and 3
a solution is made in a small beaker of a transition metal compound A
the pale green crystals of A dissolve to make a green solution B
when dilute sodium hydroxide solution is added to B a green precirpirate of C forms after leaving beaker to stand a brwon colouration D is seen at the surface of the mixture in beaker
identify transition element found in A
transition element ion found in solution B
precipitate C
substance D
and type of reaction occurred in formation of D (5)
- A - iron
- B- Fe2+/[Fe(H2O)6]2+
- C- [Fe(OH)2(H2O)4]/Fe(OH)2
- D-[Fe(H2O)6]3+/ Fe3+
- oxidation
the ligand en is NH2CH2Ch2NH2 explain how this molecule is ablt to form bonds with a transition metal ion (2)
- the nitrogen atoms on the molecule have a lone pair
- that can be donated to the transition metal to form a coordinate bond / en is bidendate so can form two bonds
the complex ion [Ni(en)3]2+
en is NH2VH2CH2NH2
which statmenets are correct
1. has a coordination number of 6
2. has a triogonal planar shape
3. has emperical forula NiCNH4 (1)
only 1
state the meaning of the term ci trans isomerism of a tranition metal complex (2)
- where complexes have the same structure
- but the ligands are orientated differently in space
isomerim can exit in complex ions
which statements are correct
1. [Ni(en)3]2+ can exist as optical isomers
2. the ion CuCl4- exhibits stereoisomerism
3. the isomers cis platin and trans platin are used as anti cancer drugs (1)
only 1
what is a precipitate (1)
whe two solutions are mixed any solid product is a precipitate
a compound of manganese (II) is dissolved in water to make solution A the solution is divided into two portions in test tubes
drops of sodium hydroxide solution are added to each portion so that precipitate B forms one test tube is the left to stand the other test tube has an excess of sodium hydroxide solution added
state the solution of colour A (1)
pale pink / colourless
a compound of manganese (II) is dissolved in water to make solution A the solution is divided into two portions in test tubes
drops of sodium hydroxide solution are added to each portion so that precipitate B forms one test tube is the left to stand the other test tube has an excess of sodium hydroxide solution added
give the formula of coloured ion A (1)
[Mn(H2O)6]2+
a compound of manganese (II) is dissolved in water to make solution A the solution is divided into two portions in test tubes
drops of sodium hydroxide solution are added to each portion so that precipitate B forms one test tube is the left to stand the other test tube has an excess of sodium hydroxide solution added
state the colour of precipitate B (1)
white
a compound of manganese (II) is dissolved in water to make solution A the solution is divided into two portions in test tubes
drops of sodium hydroxide solution are added to each portion so that precipitate B forms one test tube is the left to stand the other test tube has an excess of sodium hydroxide solution added
write the ionic equation for the formation of B(2)
- [Mn(H2O06]2+ + 2OH- ->[Mn(OH)2(H2O)4]+2H20
- Mn2+ + 2OH- ->Mn(OH)2
a compound of manganese (II) is dissolved in water to make solution A the solution is divided into two portions in test tubes
drops of sodium hydroxide solution are added to each portion so that precipitate B forms one test tube is the left to stand the other test tube has an excess of sodium hydroxide solution added
the tube darkens when left to stand why (1)
redox reaction has occcured
a compound of manganese (II) is dissolved in water to make solution A the solution is divided into two portions in test tubes
drops of sodium hydroxide solution are added to each portion so that precipitate B forms one test tube is the left to stand the other test tube has an excess of sodium hydroxide solution added
for the test tube that has excess sodium hydroxide added describe what would be observed if anything (1)
no observational change
describe fully the observations that you would make when ammonia solutionis added dropwise and then in excess to a solution of copper (II) compound giving ionic equations (6)
- blue precipitate forms
- in excess dissolves
- to form a deep blue solution
- [Cu(H2O)6]2+ + 2OH- -> [Cu(OH)2(H2O)4] +2H2O
- [Cu (OH)2(H2O)4] +4NH3 -> [Cu(NH3)4(H2O)2]2+ + 2H2O +2OH-/ Cu(OH)2 + 4NH3 + 2H2O -> [Cu(NH3)4(H2O)2]2+
when ammonia solution is added to a solution of chromium (III) compound reaction occurs in two stages in the first syade a ammonie is added fropwise a reaction occurs
describe the observation you would make (1)
write the ionic equation for this reaction giving the full formula for the complex ions (3)
- green precipitate
- [Cr(H2O)6]3+ +3OH- ->[Cr(OH)3(H2O)3] + 3H2O
when ammonia solution is added to a solution of chromium (III) compound reaction occurs in two stages in the first syade a ammonie is added fropwise a reaction occurs
what type of reaction has occurred (1)
acid - base
when ammonia solution is added to a solution of chromium (III) compound reaction occurs in two stages in the first syade a ammonie is added fropwise a reaction occurs
in the second stafe as ammonia is added in excess a further reaction occurs
describe the observation you would make (1)
write the ionicc quation for this reaction giving full formula of complex ions (3)
what reaction has occurred (1)
- the precipitate dissolves to form a violet solution
- [Cr(OH)3(H2O)3] + 6NH3 -> [Cr(NH3)6]3+ + 3OH- + 3H2O
- ligand exchange
describee how haemoglobin in the blood enables the transport of oxygen to cells (2)
- oxygen molecules bind the the molecule of haemogloin
- and are carried to the cells where they are released
explain why the build up of carbon monoxide in a room is dangerous (3)
- CO undergoes a ligand exchange reaction
- replacing oxygen attatched to haemoglobin
- preventing oxygen transport
a transition metal compound A consists of blue crystals
some of these crystals are dissolved in water to make a blue solution B a soltuion containing iodide ions is added dropwise until no further change occurs
the result is a liquid with a brown appearance C containing white precipitate D
what transition element is found in A (1)
copper
a transition metal compound A consists of blue crystals
some of these crystals are dissolved in water to make a blue solution B a soltuion containing iodide ions is added dropwise until no further change occurs
the result is a liquid with a brown appearance C containing white precipitate D
give the formula of the ion with the blue colour in B (1)
[Cu(H2O)2]2+
a transition metal compound A consists of blue crystals
some of these crystals are dissolved in water to make a blue solution B a soltuion containing iodide ions is added dropwise until no further change occurs
the result is a liquid with a brown appearance C containing white precipitate D
which molecule gives the the brown appearance to C (1)
I2
a transition metal compound A consists of blue crystals
some of these crystals are dissolved in water to make a blue solution B a soltuion containing iodide ions is added dropwise until no further change occurs
the result is a liquid with a brown appearance C containing white precipitate D
give the formula of precipitate D (1)
CUI
a transition metal compound A consists of blue crystals
some of these crystals are dissolved in water to make a blue solution B a soltuion containing iodide ions is added dropwise until no further change occurs
the result is a liquid with a brown appearance C containing white precipitate D
what type of reaction ha occurred (1)
redox reaction
give the IUPAC name for K2Cr2O7 (1)
potassium dichromate (VI)
what colour change is seen when alcohol is added to K2Cr2O7
orange to green
