Transition Elements

Question 1

what is a transition element

Answer 1

an element that can form ATLEAST 1 stable ion with a partially filled d orbital

Question 2

what happens to the electrons in 4s orbital of Cr

Answer 2

the one electron moves to the 3d orbitals so they all have one electron each- more stable

Question 3

what happens to the electrons in 4s orbital of Cu

Answer 3

one electron goes to the 3d orbital so all the 3d orbitals are full- results in the 4s orbital only having 1 electron

Question 4

why isn’t Sc a transition element

Answer 4

forms Sc3+ but has an EMPTY sub shell

Question 5

why isn’t Zn a transition element

Answer 5

forms Zn2+ but has a FULL d sub shell

Question 6

what colour is [Cu(h2o)6]2+

Answer 6

pale blue

Question 7

what happens to [Cu(h2o)6]2+ when SOME OH- is added formula of ion + colour

Answer 7

[Cu(h2o)4(OH)2] or [Cu(OH)2] and a pale blue precipitate forms

Question 8

formula of ion formed when excess NH3 is added to [Cu(H2O)6]2+ and colour

Answer 8

[Cu(NH3)4(H2O)2]2+ Dark blue solution

Question 9

what colour is [Fe(h2o)6]2+

Answer 9

pale green

Question 10

what happens to [Fe(h2o)6]2+ when SOME OH- is added formula of ion + colour

Answer 10

[Fe(h2o)4(OH)2] or [Fe(OH)2] a dirty green ppt forms

Question 11

what colour is [Fe(h2o)6]3+

Answer 11

yellow

Question 12

what happens to [Fe(h2o)6]3+ when SOME OH- is added formula of ion + colour

Answer 12

[Fe(h2o)3(OH)3] or [Fe(OH)3] a orange/ brown ppt forms

Question 13

what colour is [Mn(h2o)6]2+

Answer 13

Pale pink

Question 14

what happens to [Mn(h2o)6]2+ when SOME OH- is added formula of ion + colour

Answer 14

Mn(h2o)4(OH)2] or [Mn(OH)2] a brown ppt forms

Question 15

what colour is [Cr(h2o)6]3+

Answer 15

green

Question 16

what happens to [Cr(h2o)6]3+ when SOME OH- is added formula of ion + colour

Answer 16

[Cr(h2o)3(OH)3] or [Cr(OH)3] a green/grey ppt forms

Question 17

what happens to [Cr(h2o)6]3+ when EXCESS OH- is added formula of ion + colour

Answer 17

[Cr(OH)6]3- a Dark green solution

Question 18

formula of ion formed when excess NH3 is added to [Cr(h2o)6]3+ and colour

Answer 18

[Cr(NH3)6]3+ a purple solution

Question 19

what is a complex ion

Answer 19

a central transition metal ion is surrounded by ligands bonded by dative covalent (coordinate) bonds

Question 20

ligands have…

Answer 20

at least 1 lone pair of electrons to form a coordinate bond with the transition metal

Question 21

examples of monodentate ligands

Answer 21

H2O, NH3, CN-, Cl-

Question 22

examples of bidentate ligand (2)

Answer 22

ethandioate and ethane 1,2 diamine

Question 23

what is ligand shape determined by

Answer 23

ligand size + number of coordinate bonds

Question 24

structure of cis platin and what its used for

Answer 24

(cl)2pt(NH3)2

both the cl displace easily and bond to N atoms on the DNA of cancer cells- preventing cancer cells from reproducing

Question 25

disadvantage of cisplatin

Answer 25

prevents normal cells from reproducing - including blood cells- suppresses immune system

Question 26

when can optical isomerism occur in ligands

Answer 26

when octahedral complexes are formed by 3 bidentate ligands bonded to a central ion

Question 27

why are transition elements good catalysts

Answer 27

can change oxidation states by gaining/ losing electrons within their d orbitals- this transfer of electrons speeds up reactions. also good at adsorbing substances onto their surfaces to lower eA

Question 28

positives of using transition elements as catalysts

Answer 28

good for industry and environment- allow reactions to occur at lower temperatures and pressures.

Question 29

negatives of using transition elements as catalysts

Answer 29

health risks- some are toxic long term exposure to copper-liver +kidney damage Mn causes psychiatric problems

Question 30

what happens when carbon monoxide bonds to haem

Answer 30

replaces the water ligand- its a very strong ligand doesn't readily exchange with o2 or h2o

Question 31

oxidation of Fe2+

Answer 31

by acidified KMnO4 goes from pale green to Fe3+ (yellow)

Question 32

reduction of Fe3+

Answer 32

by I- goes from yellow to pale green Fe2+

Question 33

oxidation of Cr3+

Answer 33

oxidised to (Cr2O4)2- by warming with H2O2 in alkaline conditions.

Question 34

colour of (Cr2O4)2-

Answer 34

yellow

Question 35

how to make (Cr2O7)2-

Answer 35

add dilute h2so4

Question 36

colour of (Cr2O7)2-

Answer 36

orange

Question 37

reducing (Cr2O7)2- to Cr3+ (what is needed)

Answer 37

acidified zinc

Question 38

reducing cu2+ (what is needed and what is made)

Answer 38

I- is needed and CuI(s) is made

Question 39

colour of CuI (cu+) ppt

Answer 39

white ppt

Question 40

2CuI(s) + I2 is made from reducing Cu2+ what is observed in the test tube

Answer 40

CuI forms a white ppt and I2 results in a brown solution

Question 41

what happens to Cu+

Answer 41

readily disproportionates to produce Cu(s) and Cu2+ (aq)

Question 42

colour of Cu(s)

Answer 42

brown

Question 43

Cu(s) + Cu2+(aq) is made from disproportionation of of Cu+ what is observed in the test tube

Answer 43

Cu(s) forms a brown solid and Cu2+ forms a blue solution