Transition Elements

Question 1

Transition element

Answer 1

A d block element that can form at least one stable ion with an incomplete d sub-shell.

Question 2

Which elements are not transition elements in the d block?

Answer 2

Scandium and Zinc- because they don’t form a stable ion with a partially filled d sub shell.

Question 3

Which transition elements have a 4s1 sub shell (different from the rest) and why?

Answer 3

Cr and Cu because having a 3d5 and 3d10 sub-shell give additional stability to atoms.

Question 4

Why is scandium not a transition elements?

Answer 4

It only form one stable ion of Sc 3+ which has an empty 3d subshell (not partially filled)

Question 5

Which orbital do you remove first?

Answer 5

You remove from the 4s SUB LEVEL FIRST!!!!!!

Question 6

Why zinc not a transition element?

Answer 6

It only form 1 stable ion of Zn2+ which has a full d subshell (not partially filled)

Question 7

What are the three main properties of transition metal?

Answer 7

• Variable oxidation states
• Form coloured ions
• Good catalysts

Question 8

Why do transition metals have variable oxidation states?

Answer 8

Because 4s and 3d sub levels are so close

Question 9

What are some processes where a transition metal is used as a catalyst

Answer 9

• Haber process (Iron)
• Hydrogenation of alkenes
  (Heterogenous catalyst)

Question 10

What formula do metal ions have dissolved in water?

Answer 10

[M(H2O)6]^n+

Question 11

Ligand

Answer 11

Molecule or ion that donates a pair of electrons to a central metal ion to form a dative covalent bond.

Question 12

Coordination number

Answer 12

Number of dative coordinate bonds attached to the central atom

Question 13

Monodentate ligands + examples

Answer 13

Donates one lone pair and forms one coordinate bond to a metal ion.
H2O:
:NH3
:CN-
:Cl-

Question 14

Bidentate ligands + examples

Answer 14

Donates 2 lone pairs and forms two coordinate bonds to a metal ion.
- Ethanedioate
- Ethane-1,2- diamine

Question 15

Ligands with more than two coordinate bonds

Answer 15

Multidentate ligands

Question 16

Examples of small ligands

Answer 16

H2O:, :NH3, :CN- —> can fit 6 around a central metal (octahedral)

Question 17

Examples of larger ligands

Answer 17

:Cl- (fits 4 bonds) and 1,2- diaminoethane + ethanedioate ion (normally forms 3)

Question 18

Example of square planar complex

Answer 18

Pt[(NH3)2Cl2)aq (cis platin)

Question 19

Total oxidation state of metal equation

Answer 19

Total oxidation state - total oxidation state of ligands

Question 20

Optical isomerism in complex ions

Answer 20

Octahedral complexes with 3 bidentate ligands form non-superimposable images.

Question 21

What type of stereoisomerism do complexes show?

Answer 21

• Cis-trans isomerism
• Octahedral complexes

Question 22

Cis-trans isomerism

Answer 22

• Octahedral complexes with 4 ligands of the same type and 2 ligands of a different type display cis- grands isomerism.
  180= opposite = trans
  <180= adjacent = cis
  -Square planar complexes with 2 ligands of the same type and 2 ligands of different type display cis-trans isomerism

Question 23

How do ligand substitution reaction allow haemoglobin to transport oxygen in blood?

Answer 23

Oxygen bonds to Fe2+ and when required O2 is released (equilibrium)

Question 24

What makes a molecule a square planar

Answer 24

• Complex has no more than two identical ligands attached to the central metal ions
• 90” bond angle

Question 25

Describe the action of one of platin stereoisomers in cancer treatment

Answer 25

The cis isomers binds the cancer cell’s DNA and stops it from replicating