Transition Elements

Question 1

A d-block element is an element that:

Answer 1

Have their highest energy electron in a d sub-shell

Question 2

A transition element is a d-block element that:

Answer 2

Forms an ion with an incomplete d sub-shell

Question 3

Explain why two of the d-block elements in period 4 (Sc - Zn) are not transition elements (use electron configurations in your answer) :

Answer 3

Sc is not a transition element as its ion has an empty sub-shell.
Sc^3+ : 1s2 2s2 2p6 3s2 3p6
Zn is not a transition element as it has a complete d sub-shell in its only ion.
Zn^2+ : 1s2 2s2 2p6 3s2 3p6 3d10

Question 4

What is chromium’s electron configuration?

Answer 4

1s2 2s2 2p6 3s2 3p6 4s1 3d5

Question 5

What is copper’s electron configuration?

Answer 5

1s2 2s2 2p6 3s2 3p6 4s1 3d10

Question 6

What is Cu^2+ ion electron configuration?

Answer 6

1s2 2s2 2p6 3s2 3p6 3d9

Question 7

What is Fe^3+ ion electron configuration?

Answer 7

1s2 2s2 2p6 3s2 3p6 3d5

Question 8

What sub-shell are electrons lost from first ?

Answer 8

4s sub-shell

Question 9

Transition elements have typical metallic physical properties. Typical properties of transition elements (that make them different from other metals) are chemical properties, these are:

Answer 9

1. Variable oxidation states
2. Act as catalysts
3. Form coloured compounds.

Question 10

Transition elements are effective catalysts as they can change…

Answer 10

… Oxidation states.

Question 11

Give an example of a process that uses the transition element nickel as a catalyst and give an equation.

Answer 11

Process: hydrogenation of alkenes
Ni
C2H4 + H2 —-> C2H6

Question 12

Give an example of a process that uses the transition element iron as a catalyst and give an equation.

Answer 12

Process: Haber process

N2(g) + 3H2(g) —–> 2NH3(g)
(reversible reaction)

Question 13

Give an example of a process that uses the transition element MnO2 as a catalyst and give an equation.

Answer 13

Process: Decomposition of hydrogen peroxide

2H2O(aq) —-> O2(g) + 2H2O(l)

Question 14

A complex ion is a transition metal ion bonded to:

Answer 14

one or more ligands by coordinate (dative covalent) bonds

Question 15

A ligand is:

Answer 15

A molecule or ion that can donate a pair of electrons to form a coordinate bond with the transition metal ion.

Question 16

The coordination number is:

Answer 16

Total number of coordinate bonds formed between central metal ion and its ligands.

Question 17

Give an example of a complex ion with an octahedral shape and a coordination number of 6.

Answer 17

[Co(H2O)6]^2+

Question 18

Give an example of a complex ion with a tetrahedral shape and a coordination number of 4.

Answer 18

[CuCl4]^2-

Question 19

Give an example of a complex ion with a square planar shape and a coordination number of 4.

Answer 19

[Ni(NH3)2Cl]

Question 20

A Monodentate ligand is a ligand that:

Answer 20

donates 1 pair of electrons (e-) to form one bond (1 bite)

Question 21

Square planar only occur with:

Answer 21

group ten elements e.g Ni,Pd,Pt

Question 22

A Bidentate ligand is ligand that:
Give examples.

Answer 22

is a single molecule/ion with 2 lone pairs that can each form a coordinate bond to a central metal ion
e.g Ethane 1,2 diamine
e.g Ethane dilate ion

Question 23

The 2 different types of stereoisomerism in complex ions are:

Answer 23

1. Cis (same ligands at 90 degrees) / Trans isomerism (same ligands at 180 degrees)
2. Optical isomers = Non-superimposable mirror images.