Transition Metals

Question 1

How are transition metals defined?

Answer 1

as metals with an incomplete d subshell in at least one of their ions

Question 2

What are the exceptions to the Aufbau principle?

Answer 2

chromium and copper

Question 3

What is the electronic configuration of chromium?

Answer 3

Ar3d⁵4s¹

Question 4

What is the electronic configuration of copper?

Answer 4

Ar3d¹⁰4s¹

Question 5

Why are chromium and copper exceptions?

Answer 5

due to the special stability of all the d orbitals being half-filled

Question 6

Which are more stable, full or half-filled orbitals?

Answer 6

full orbitals

Question 7

What can be said about transition metals?

Answer 7

they can form ions with a variety of oxidation states

Question 8

What is the oxidation number of an atom in an element?

Answer 8

zero

Question 9

What is the oxidation number of a monatomic ion?

Answer 9

it is equal to the charge on the ion

Question 10

What can oxidation numbers be used to determine?

Answer 10

whether an oxidation or reduction reaction has taken place

Question 11

What does an increase in oxidation number indicate?

Answer 11

an oxidation reaction

Question 12

What does a decrease in oxidation number indicate?

Answer 12

a reduction reaction

Question 13

What are compounds containing metals in high oxidation states said to be?

Answer 13

oxidising agents

Question 14

What are compounds with metals in low oxidation states said to be?

Answer 14

reducing agents

Question 15

What can be said about redox reactions?

Answer 15

they are often accompanied by a colour change

Question 16

What does a complex consist of?

Answer 16

a central ion surrounded by ligands

Question 17

What are ligands?

Answer 17

electron donors; they may also be negative ions or molecules with non-bonding pairs of electrons

Question 18

What is a dative bond?

Answer 18

a bond where the electron forming the bond comes from the same atom

Question 19

What is the coordination number?

Answer 19

the number of bonds from the central metal ion to the ligand

Question 20

What does the coordination number determine?

Answer 20

the shape of the complex ion

Question 21

What are the secondary colours?

Answer 21

yellow, cyan and magenta

Question 22

What are the primary colours?

Answer 22

red, green and blue

Question 23

What happens when one colour is removed from the white light?

Answer 23

the colour remaining is the complementary colour

Question 24

Why are compounds coloured?

Answer 24

• they absorb radiation from the visible spectrum

* the colour of a compound is that of the light which is not absorbed

Question 25

Why can transition metals absorb light?

Answer 25

because they have incomplete d-orbitals

Question 26

How is an electrostatic field in a complex formed?

Answer 26

due to the central ion being surrounded by ligands

Question 27

What does electrostatic repulsion do?

Answer 27

it raises the energy of electrons in orbital

Question 28

d-d splitting

Answer 28

* d-d splitting creates a small energy gap for the electrons to jump. * The electrons then jump the gap by absorbing radiation from the visible spectrum * as the electrons become excited they jump energy levels thus creating unpaired electrons

Question 29

What is the difference between two sets of orbitals known as?

Answer 29

the crystal field strength

Question 30

What does the energy difference between two sets of d orbitals depend on?

Answer 30

the position of the ligand in the spetrochemical series

Question 31

Why do transition metals absorb visible light?

Answer 31

•when the transition metal absorbs light, electrons can be promoted from one of the lower d orbitals to one of the higher d orbitals and so the complementary colour is absorbed

Question 32

What can transition metals be used in?

Answer 32

catalysis