Chapter 24 TRANSITION ELEMENTS

Question 1

Why are d block elements called them again

Answer 1

Because the highest energy sub shell is thr D sub shell

Question 2

What are the TWO EXCEPTIONS to electron filling in the D block elements
Why?

Answer 2

Chromium 3D5 4s1
Copper 3D10 4s1

Believed to give more stability : half filled 3d5 and full filled 3d10 is more stable then without

Question 3

What are transition elements DEFINITION

Answer 3

This is elements that form at least one ion with a PARTIALLY FULL D SUB SHELL

Question 4

So why are scandium and zinc not considered transition elements, even tho are in the d block?

What ions they form?

Answer 4

Because scandium IONS has no electrons in d orbitals, and zinc IONS has full electrons in d orbitals

Definition = partially full d orbitals when ions made, thus not transition

2) sc = sc 3+, Zn = Zn2+

Question 5

What are the 3 characteristic properties of transitions metals and their compounds?

Answer 5

1) form compounds where the transition element can have DIFFERENT OXIDATION STATE
2) Form COLOURED COMPOUNDS
3) Elements and compounds can act as CATALYSTS

Question 6

What happens when a transitions metal changes it’s oxidation state

Answer 6

It’s colour changes.
For example chromium cr3+ is green and cr6+ is orange

So in dichromate test it goes from orange to green as it gets reduced , as it itself is an oxisising agent

Question 7

What oxidation state can all the transition elements take at least

Answer 7

+2 each time, some more

Question 8

Colours of IRON 2 and Iron 3, and chromium 3 and 6 in solution

IMPORTANT= THESE COLOURS ONLY SHOW IN WHAT FORM

Answer 8

Iron 2 = pale green
Iron 3 = yellow

Chromium 6 = orange
Chromium 3 = green
(Remember chromium is oxidising agent so it becomes reduced, and gains electrons, so oxidation number goes down)

2) ONLY SHOW WHEN IN SOLUTION THUS AQEUOUS! NOT AS A COMPOUND

Question 9

3 examples of catalysts of transition metals
Haber
Contact
Zinc

Answer 9

Haber process
N2 +3H2 —> 2Nh3 uses IRON CATALYST

Contact process
2So3 + o2 —> 2So3
Uses V2O5 (S)

Zinc and acid
Zn + h2so4 —> ZnSo4 + H2
CU 2+ IONS

Question 10

Homo heterogenous catalysts again

Answer 10

Homo is same state, hetero different like contact and Haber process

Question 11

What are the benefits of a catalyst again
SPEC ANSWER (2)

Answer 11

• reduced energy usage
• reduced risks of toxicity from the transition metals

Question 12

What is a complex ion

What is a LIGAND

What is the coordination number!

Answer 12

When one more ligand binds ti a central metal ion

A ligand is a molecule or ion that has a lone pair and donates it to the central metal ion to form a dative bind / coordinate bind

Coordination number is the number of coordinate binds in thst complex metal ion

Question 13

Monodentate vs bidenatet etc

Answer 13

If it can donate two lone pairs = bi

Question 14

What are the 5 different monodenate ligands and more IMPORTANTLY which ones REDUCE THE CHARGE

Answer 14

Water , ammonia neutral

Cl- , OH-, CN-

Question 15

Bide are ligands en and oxalate?

Charge for oxalate ion?

Answer 15

EN is 1 2 diamino ethane , so two amino groups

Oxalate ion is c=o and connected to an O- twice
COO-COO-

Oxalate ions reduce the charge by 2

Question 16

Shapes of complex ions based on coordination number

When is it 6, when is it 4!!! (+ why)

Answer 16

1) 6 = octahedral (90°) , 4 could be tetrahedral (109.5°) or SQAURE PLANAR (90°)

The coordinate number will be 6 for a standard element as long as the ligand is NOT CHLORINE
- chlorine atoms are BIG, so when they are present, the coordination number is capped at 4

Question 17

WHEN IS IT A SQAURE PLANAR (regardless of ligand) (3)

Describe square planar shape

Answer 17

This is because if the central metal ion is PALADIUM , PLATINUM OR GOLD , then it automatically becomes SQUARE PLANAR

2)
- Has 4 ligands , 2 wedge 2 not
- 90°

Question 18

Again what 3 elements does square planar automatically come

Answer 18

Palladium platinum and gold

So basically 8 electrons in d sub shell

Question 19

Cos trans isomerism in sqaure planar?

Answer 19

Two atoms must be the same. If these atoms next ti each other = cis 90°
If they are opposite each other = trans 180°

Question 20

Cis trans in octahedral

How is cis and trans shown

Answer 20

In this case the rest of ligands might be the same but you want TWO STANDOUT SAME

Again if they are right next to each other = cis
IF DIRECTLY OPPOSITE THEN TRANS

Question 21

Cis trans isomerism in octahedral but BIDENTATE?

Answer 21

If bidentate , it’s gonna be that there will be two bidentate ligands which take up 4 space and two normal

Look at two normal, again next to = cis, oppsote = trans

Question 22

Optical isomerism only for OCTAHEDRAL

Why are they not the same if rotate

Answer 22

This is two non superimposable mirror images

So thing about it you can’t rotate because if you did the ones going into the page would be going out

Question 23

Cis trans isomerism for DNA

Answer 23

CIA Platin helps treatment in cancer by binding to dna in turn our cells and thus preventing them from diving

But has unpleasant side effects

Still used tho