Transition Metals

Question 1

Transition metals forming positive ions

Answer 1

4s Electrons are lost before the electrons occupying 3d orbitals

Question 2

What kind of d orbitals have a special stability

Answer 2

Half filled or fully filled

Question 3

Transition metals are defined as

Answer 3

Metals with incomplete d sub shell in at least one of their ions

Question 4

Aufbau principle

Answer 4

states that in the ground state of an atom or ion, electrons fill subshells of the lowest available energy, then they fill subshells of higher energy.

Question 5

What are the excpetions to the aufbau principle?

Answer 5

Chromium and Copper atoms, where the added stability of the half filled/ completely filled d orbitals results in 4s being half filled

Question 6

An element has a particular oxidation state when

Answer 6

It had a specific oxidation number

Question 7

Ligands

Answer 7

Negative ions or molecules with non bonding pairs of electrons which they donate to the central metal atom/ion forming DATIVE COVALENT BOND

Question 8

Ligands can be

Answer 8

Mono-dentate- Donates one pair of electrons to form a dative covalent bond
Bidentate- Donates two pairs of electrons
all the way up to hexadentate

Question 9

Coordination number

Answer 9

The total number of bonds from the ligands to the central transitional metal atom/ion

Question 10

When are d orbitals no longer degenerate?

Answer 10

In a transition metal complex

Question 11

Transition metal complex

Answer 11

Consists of a central metal ion surrounded by ligands

Question 12

Why does

Splitting of d orbitals to higher and lower energies occur

Answer 12

When the electrons present in the approaching ligands cause the electrons in the orbitals lying along the axes to be repelled

Question 13

What are

Strong field ligands

Answer 13

Ligands that cause a large difference in energy between subsets of d orbitals

Question 14

When is

Light absorbed in a transtion metal complex

Answer 14

When electrons in a lower energy d oribtal are promoted to higher energy d orbital

Question 15

Dative covalent bond

Answer 15

One atom provides both electrons of the bonding pair, same as any other covalent bond

Question 16

Oxidation number determines

Answer 16

if oxidation or reduction has occurred

Question 17

Rules for assigining oxidation number

Answer 17

• OXN of an uncombined element is 0
  – Ions of single atoms have same OXN as their charge
• Sum of all OXN in molecule has to be 0
  – Sum of all OXN numbers on a polyatomic ion is equal to charge on the ion.

Question 18

Why may transition metals have different colours

Answer 18

Differing oxidation states

Question 19

Copper and iron when naming negative complexes

Answer 19

Cuprate and ferrate, everything else add an Ate to the end

Question 20

common ligands with a 2- charge

Answer 20

Oxido 0 2-, Oxalato O4C2 2-

Question 21

Blue light is absorbed

Answer 21

Red and green are transmitted, with a yellow colour complex.

Question 22

The colour being observed is the

Answer 22

Complementary colour to the colour of wave length thats absorbed

Question 23

why will colours of the same transition metal be different ?

Answer 23

When different ligands are attached to the t metal, energy absorbed will change, resulting in different wavelengths of light being transmitted. Ligands produce different crystal field splittings.

Question 24

Ligand field strength is due to iys

Answer 24

Place in the spectrochemical series.

Question 25

Why are transition metals able to absorb light

Answer 25

The 5 d orbitals split in term of energy, they are no longer degenerate, due to electron repulsion when the ligands attach to t metal. When electrons are promoted to the higher energy level d orbitals light is absorbed.

Question 26

Spectrochemical series decreasing

Answer 26

Weaker field Smaller energy difference Longer wavelength absorbed

Question 27

# how Ultraviolet radiation absorbed | appears

Answer 27

Will appear colourless, our eyes are unable to detect the UV radiation thats been removed from the transmitted light.

Question 28

Complexes that absorb ultraviolet radiation

Answer 28

Will have strong field ligans, which cause a greater energy gap and will require higher energy for d-d transitions.

Question 29

Why would zinc not produce coloured compounds?

Answer 29

Zinc does not hace incomplete d orbitals in its io, so no d-d trantions can take place as all orbitals are full.

Question 30

# Transition metals as Catalysts

Answer 30

Transition metals and their complexes can be catalysts. -You can have heterogeneous(same Phase as reactanats) -or heterogenous (diff phase)

Question 31

# How can Heterogenous catalysts be explained

Answer 31

Adsorption of the reactive molecules onto the active sites allows reaction to be catalysed. The presence of empty d orbitals/unpaired electrons is thought to allow this. | Lowering activation energies

Question 32

# How can Homogenous catalysts be explained

Answer 32

They can form intermediate complexes with the reactive molecules resulting in a change in oxidation state

Question 33

Three main characteristics of a transition metal

Answer 33

- Produces ions of differing oxidation states - Produce coloured componds - They can act as catalysts