Transition Metal Elements

Question 1

Why are they called transition metal elements

Answer 1

1. They have partially filled d orbitals

Question 2

How many d-orbitals are there with the same radial function for a given PQN

Answer 2

1. 5

Question 3

What is l and ml number for 3d orbital

Answer 3

1. l= 2 (d-orbital)

2. ml= -2,-1,0,1,2 (5 different orientations of d-orbitals)

Question 4

What is 1 radial unit in anstrongs

Answer 4

0.529 A

Question 5

How many radial nodes does 3d orbital have

Answer 5

1. 0 nodes at r>0

Question 6

Why is dz^2 orbital a weird shape

Answer 6

1. Schrodinger provides 6 solutions for l=2, but only 5 orbitals- 5 allowed values of ml
2. Two solutions dz^2-x^2 and dz^2=y^2 orbitals are combined to give dz^2 orbital

Question 7

Why do each of the d-orbitals have a spatial shape and/or orientation

Answer 7

1. Each of the 5 d-orbitals has a different angular function

Question 8

Why are p,d and f orbitals no spherical but s-orbitals are

Answer 8

1. For s-orbitals Y(θ,ϕ) has a fixed value

2. But for the rest Y(θ,ϕ) the angular wavefunction does vary

Question 9

How do you remember the diagrams of d-orbitals

Answer 9

1. Orbitals with squared labels - have lobes along ‘squared’ axis
2. Orbitals without squared labels- lobes directed between axis in orbital label

Question 10

What is the rdf max

Answer 10

1. R at max in rdf function

2. Most likely distance from nucleus of finding an e- in an orbital

Question 11

state which of 3d and 4s orbitals are higher in energy

Answer 11

1. 3d orbitals are higher in energy than 4s orbitals

2. However in forming cations and complexes 4s electrons are lost first

Question 12

Describe difference in energy between 3d and 4s orbitals

Answer 12

1. rdf max for the 4s orbital > rdf max for the 3d orbital
2. But 4s fills before 3d
3. When empty the 4s has lower energy than 3d because the 4s penetrates the 3d
4. This means that sometimes the 4s e- can get closer to the nucleus than the 3d e-, lowering the energy of the 4s orbital
5. When occupied, the 4s energy raised above that for the 3d
6. Hence 4s e- is lost before 3d e- when forming ions in the d-block

Question 13

What are the properties when a transition metal compound have d^n metal configuration where n is odd

Answer 13

1. Essentially has free radicals
2. But these radicals don’t show extreme reactivity
3. Paramagnetism results when there is an odd number of electrons
4. Unpaired electrons in d block complexes give rise to paramagnetic behaviour

Question 14

What are the colours of d block metal compounds characteristic of and what are exceptions

Answer 14

1. Species with incompletely filled d-orbitals
2. This does not apply d0 or d10 configurations such as Sc3+ or Zn2+
3. Colour intensities are usually weak compared to dyes

Question 15

What is the difference in colour between transition metal compounds and main group compounds

Answer 15

1. Main group compounds are usually coloured as a result of the ligands or counter ions present (not the metal)

Question 16

What is the electronic configuration for Br-

Answer 16

1. [Ar]4S2,3d10,4p6

Question 17

What is the electronic configuration for Ag

Answer 17

1. [Kr]5s1,4d10

Question 18

What is the electronic configuration for Pb

Answer 18

1. [Xe] 4f145d106s26p2

Question 19

How many unpaired electrons does Co3+, Mo and Ni2+ have

Answer 19

1. 4
2. 6
3. 2

Question 20

What happens to electrons in compounds containing transition metals

Answer 20

1. Electrons in outer s-orbitals will always move to the d-orbitals as this gives a lower energy arrangement

Question 21

Describe bonding in [Ni(H2O)6]

Answer 21

1. 2-center, 2-electron metal ligand interactions in coordination compounds- dative bonds
2. Oxygen has lone pair

Question 22

What is a dative bond

Answer 22

1. The pair of electrons arise from the same atom