Transition metal

Question 1

which block on the periodic table is mostly transition elements?

Answer 1

D block

Question 2

what is a transition metal?

Answer 2

a transition metal is a metal that can form one or more stable ions with partially filled d sub-shell

Question 3

how many electrons can a d subshell hold?

Answer 3

10

Question 4

which two elements in d block are not transition metals?

Answer 4

Scandium and zinc

Question 5

can you write the full electronic configuration of Cr?

Answer 5

[Ar] 3d5 4s1

Question 6

which two elements have only one electron in 4s sub-shell

Answer 6

Cr and Cu

Question 7

how many electrons does Cr have in its 3d sub-shell

Answer 7

5

Question 8

how many elecrons does Cu have in its 3d sub-shell

Answer 8

10

Question 9

how many elecrons does Cu have in its 4s sub-shell

Answer 9

1

Question 10

why Sr and Zn aren’t transition metals?

Answer 10

their stable ions don’t have partially filled d-subshells.

Question 11

what ion does Sr form? and how many elecrons are in their d subshell?

Answer 11

Sr3+, none

Question 12

what ion does Zn form? and how many elecrons are in their d subshell?

Answer 12

2+, 10

Question 13

can you write the full electronic configuration of Fe2+

Answer 13

[Ar] 3d6

Question 14

which sub shell will lose electrons first when transition metals form ions?

Answer 14

4s sub shell

Question 15

can you write the full electronic configuration of Cr3+

Answer 15

[Ar] 3d3

Question 16

what are the physical properties of transition metals? (3)

Answer 16

1. they all have a high density
2. they all have a high melting and boiling points
3. their ionic radii are more or less the same

Question 17

what are their chemical properties? (4)

Answer 17

1. they can form complex ions
2. they from coloured ions
3. they’re good catalysts
4. they can exist in cariable oxidation states

Question 18

how many ions can vanadium form? and what charges are they?

Answer 18

4, +2, +3, +4, +5

Question 19

what is colour of V2+

Answer 19

violet

Question 20

what is colour of V3+

Answer 20

green

Question 21

what is colour of VO2+

Answer 21

blue

Question 22

what is colour of VO2+

Answer 22

yellow

Question 23

what is colour of Cr3+

Answer 23

green/violet

Question 24

what is colour of Cr2O72-

Answer 24

orange

Question 25

what is colour of Mn2+

Answer 25

pale pink

Question 26

what is colour of MnO4-

Answer 26

purple

Question 27

what is colour of Fe2+

Answer 27

pale green

Question 28

what is colour of Fe3+

Answer 28

yellow

Question 29

what is colour of Co2+

Answer 29

pink

Question 30

what is colour of Ni2+

Answer 30

green

Question 31

what is colour of Cu2+

Answer 31

blue

Question 32

why transition elements have variable oxidation states?

Answer 32

because the energy levels of the 4s and 3d subshells are very close to one another. so different numbers of electrons can be gained or lost using fairly similar amounts of energy

Question 33

what is a ligand?

Answer 33

A ligand is a species which can use its lone pair of electrons to form a dative covalent bond with a transition metal.

Question 34

examples of ligands

Answer 34

H2O, NH3, Cl-, OH-, CN-,

Question 35

what is the coordination number

Answer 35

The number of lone pairs of electrons which a cation can accept is known as the coordination number of the cation. It depends on the size and electronic configuration of that cation, and also on the size and charge of the ligand. 6 is the most common coordination number, although 4 and 2 are also known.

Question 36

6-coordinate complexes are all __________.

Answer 36

octahedral

Question 37

4-coordinate complexes are generally_______, and are formed with _______ ligands.

Answer 37

tetrahedral, larger

Question 38

2-coordinate complexes are in general ________ , and are formed with _____ ions.

Answer 38

linear, Ag+

Question 39

The rules covering the likely coordination number of transition metal complexes are:

Answer 39

a) Silver ions form linear complexes with a coordination number of 2;
b) Chloride ions and other large ions form tetrahedral complexes with a coordination number of 4;
c) Most other transition metal complexes are octahedral with a coordination number of 6.

Question 40

A d-block element is an element which has at least one__________ and at least one _______ .

Answer 40

A d-block element is an element which has at least one s-electron and at least one d-electron.

Question 41

In chromium the 4s1 3d5 structure is adopted because

Answer 41

the repulsion between two paired electrons in the 4s orbital is more than the energy difference between the 4s and 3d subshells. It is thus more stable to have unpaired electrons in the higher energy 3d orbital than paired electrons in the lower energy 4s orbital.

Question 42

The oxidation state formed by an element in its compounds is determined by

Answer 42

the maximum number of electrons it can lose without requiring so much energy to remove the electrons that the energy cannot be recovered in bonding.

Question 43

The oxidation states most commonly formed by the first-row d-block elements are as follows:

Answer 43

Sc: +3 only (d0)
Ti: +3 (d1), +4 (d0)
V: +2 (d3), +3 (d2), +4 (d1), +5 (d0)
Cr: +3 (d3), +6 (d0)
Mn: +2 (d5), +3 (d4), +4 (d3), +6 (d1), +7 (d0)
Fe: +2 (d6), +3 (d5)
Co: +2 (d7), +3 (d6)
Ni: +2 (d8)
Cu: +1 (d10), +2 (d9)
Zn: +2 only (d10)

Question 44

Cations which form complex ions must have two features:

Answer 44

• they must have a high charge density, and thus be able to attract electrons from ligands.
• they must have empty orbitals of low energy, so that they can accept the lone pair of electrons from the ligands.