Transition metals

Question 1

What is a complex ion

Answer 1

Where a transition metal ion is surrounded by ligands bonded by dative covalent bonds

Question 2

What is a ligand

Answer 2

An ion, atom or molecule that has atleast one lone pair of electrons

Question 3

What is a transition metal

Answer 3

A d block element that can form atleast one stable ion with a partially filled d subshell

Question 4

Why aren’t scandium and zinc transition metals

Answer 4

Sc3+ has an empty d subshell
Zn2+ has a full d subshell

Question 5

Properties of transition metals

Answer 5

Variable oxidation states
Coloured ions in solution
Good catalysts

Question 6

What is a monodentate ligand and examples

Answer 6

Ligand with one lone pair eg H2O, NH3, Cl-

Question 7

What is a bidentate ligand and examples

Answer 7

Ligand with 2 lone pairs eg ethandioate, ethane1-2-diamine

Question 8

What is a multidentate ligand and examples

Answer 8

3 or more lone pairs of electrons, EDTA4-

Question 9

What are optically active isomers

Answer 9

they can form a non superimposible mirror image

Question 10

What does a coordination number of 2 mean

Answer 10

Linear shape
180 degrees

Question 11

What does a coordination number of 4 mean

Answer 11

Tetrahedral - 109.5 degrees
Square planar - 90 degrees - cisplatin - anticancer

Question 12

What does a coordination number of 6 mean

Answer 12

Octahedral
90 degrees

Question 13

Which complexes show isomerism

Answer 13

Octahedral complexes with 3 bidentate ligands

Question 14

How to tell is trans or cis isomerisms

Answer 14

Trans - through - 180
Cis - 90

Question 15

What is d orbital splitting

Answer 15

The d subshell is split into 2 when ligands bond with central metal ion

Question 16

What causes d orbitals split

Answer 16

Electrons absorb light energy and get excited and move up to a higher energy level
energy from light must = delta E

Question 17

What is delta E dependent on

Answer 17

Central metal ion and its oxidation state
Type of ligand
Coordination number

Question 18

What is the equation for delta E

Answer 18

deltaE = hv = hc/wavelength

delta E = J
h = planks constant
v = frequency of light Hz
c = speed of light 3x10-8 ms-1
wavelength = m

Question 19

What effect does deltaE have on light absorbed

Answer 19

The larger the deltaE the higher the frequency of light absorbed

Question 20

Which ligands form the most stable complexes and what is the chelate effect

Answer 20

Multidentate ligands
Increasing entropy = more stable
This is the chelate effect

Question 21

What is vanadium reduced by

Answer 21

Zinc in an acidic solution

Question 22

What does redox potential tell us about stability

Answer 22

The least stable ions have the largest redox potential and are more likely to be reduced

Question 23

What is the effect of pH on electrode potential

Answer 23

The more acidic the solution the larger the electrode potential

Question 24

How does tollens reagent work

Answer 24

Ag+ is reduced to produce a silver mirror. Aldehyde is oxidised to a carboxylic acid

Question 25

What is a homogenous catalyst and example

Answer 25

The catalyst is in the same physical state or phase as the reactants
eg enzymes

Question 26

What is a heterogenous catalyst and example

Answer 26

The catalyst is in a different state of phase to the reactants
eg iron in haber cycle, iron is solid, reactants are gases
Work by chemisorption

Question 27

Explain catalyst poisoning

Answer 27

Heterogenous catalysts can be poisoned, the active sites become blocked and inactive

Question 28

What is autocatalysis and explain its effect on rate

Answer 28

When the product in a reaction acts as a catalyst for the reaction
Initially slow but as more product formed rate increases dramatically then slows as conc of reagent decreases