unit 1a: transition metals

Question 1

transition metals

Answer 1

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

Question 2

variable valency

Answer 2

transition metals can form ions with different charges by losing different numbers of electrons

Question 3

scandium and zinc

Answer 3

these are not transition metals as there is not an incomplete d-subshell in the ions they form

Question 4

properties

Answer 4

form coloured ions, form complexes, variable oxidation states, show catalytic activity

Question 5

oxidation state

Answer 5

an element is said to be in a particular oxidation state when it has a specific oxidation number, related to the number of electrons the species has lost or gained

Question 6

oxidation number in a free element

Answer 6

0 e.g. Mg=0 and Cl2=0

Question 7

for monatomic ions, the oxidation number is

Answer 7

equal to the charge, e.g. Cl^-1=-1 and Al^3+=+3

Question 8

oxidation number for oxygen

Answer 8

-2

Question 9

oxidation number for hydrogen

Answer 9

+1

Question 10

group 1 metals and group 2 metals

Answer 10

+1 and +2

Question 11

oxidation number in compounds

Answer 11

fluorine, the CN^-1 ion, and all of group 7 is always equal to -1

Question 12

in molecule the sum of all oxidation numbers is

Answer 12

equal to 0, e.g. H20=0

Question 13

in a polyatomic ion, the sum of the oxidation numbers is

Answer 13

equal to the charge of the ion, e.g. SO4^2-=-2

Question 14

oxidation involves

Answer 14

increase in oxidation number

Question 15

reduction involves

Answer 15

decrease in oxidation number

Question 16

metals high in oxidation states tend to be good

Answer 16

oxidising agents

Question 17

what two elements in the box are not transition metals

Answer 17

scandium and zinc

Question 18

redox acronym

Answer 18

OILRIG

Question 19

ligand definition

Answer 19

electron donors, may be negative ions or molecules with non-bonding pairs of electrons

Question 20

a complex consists of

Answer 20

a central metal ion surrounded by ligands

Question 21

dative bond

Answer 21

when both electrons of the shared pair come from the same atom

Question 22

ligands have at least

Answer 22

one lone pair of electrons

Question 23

monodentate

Answer 23

when a ligand uses just one atom to bind to the central metal

Question 24

bidentate

Answer 24

when a ligand uses two atoms to bind to the central metal

Question 25

example of a hexadentate ligand

Answer 25

ethylenediaminetetraacetate- EDTA

Question 26

monodentate ligands- negative ions

Answer 26

fluoride F- , chloride Cl- , cyanide CN-

Question 27

monodentate ligands- neutral molecules

Answer 27

water H2O , ammonia NH3

Question 28

bidentate ligand- negative ion

Answer 28

oxalate C2O4^2-

Question 29

coordination number

Answer 29

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

Question 30

if the complex ion is negative the transition metal name will end in

Answer 30

-ate

Question 31

if the ligand is a negative ion the name in complex will

Answer 31

replace the “e” ending with “o” e.g. bromine —> bromido

Question 32

CO name in complex ion

Answer 32

carbonyl

Question 33

H2O name in complex ion

Answer 33

aqua

Question 34

NH3 name in complex ion

Answer 34

ammine

Question 35

Fe name in complex ion

Answer 35

ferrate

Question 36

Cu name in complex ion

Answer 36

cuprate

Question 37

coordination compound

Answer 37

when a complex ion combines with oppositely charged ions

Question 38

if the complex is a positive ion it will appear

Answer 38

first in the formula and the name

Question 39

if the complex is a negative ion

Answer 39

it will appear last in the formula and the name

Question 40

three primary colours of visible light

Answer 40

red , green , and blue

Question 41

complementary colour

Answer 41

transmitted light from certain chemicals(when white light shines on certain chemicals they may absorb some of the. visible light, the colour we see is the white light minus absorbed light)

Question 42

when red light is absorbed

Answer 42

blue and green are transmitted and cyan is observed

Question 43

when blue light is absorbed

Answer 43

red and green are transmitted and yellow is observed

Question 44

when green light is absorbed

Answer 44

red and blue are transmitted and magenta is observed

Question 45

a more concentrated soloution will absorb more

Answer 45

light than a dilute solution and be darker in colour

Question 46

extent of d orbital splitting factors

Answer 46

the metal involved , the oxidation state of the metal , the nature of the ligand

Question 47

spectra chemical series

Answer 47

CN-, NH3, H2O, OH-, F-, Cl-, Br-, I-

Question 48

start of the spectrochemical series

Answer 48

weaker field , smaller delta , longer wavelength

Question 49

end of the spectrochemical series

Answer 49

stronger field , larger delta , shorter wavelength

Question 50

weakest at splitting d orbitals

Answer 50

I-

Question 51

strongest at splitting d orbitals

Answer 51

CO

Question 52

crystal field theory

Answer 52

explains how transition metals (with an incomplete 3d subshell) are coloured, only applies to octahedral complexes

Question 53

splitting

Answer 53

as a result of ligands approaching and bonding to the metal, the five 3d orbitals are no longer degenerate

Question 54

delta

Answer 54

the splitting energy

Question 55

d to d transition

Answer 55

when any of the three lower d orbitals absorb energy and are promoted to one of the two higher energy d orbitals

Question 56

how the metals transmit the colours

Answer 56

if the energy absorbed is equal to a wavelength of light in the visible spectrum, the compound will transmit its complementary colour

Question 57

catalyst of the haber process

Answer 57

iron

Question 58

catalyst of the contact process

Answer 58

vanadium (V) oxide

Question 59

catalyst of the ostwald process

Answer 59

platinum

Question 60

catalyst for catalytic converters in cars

Answer 60

platinum , palladium , rhodoum

Question 61

catalyst for the production of methanol

Answer 61

copper

Question 62

catalyst for the hardening of oils to fats

Answer 62

nickel

Question 63

catalyst for the polymerisation of alkenes

Answer 63

titanium compounds

Question 64

how catalysts speed up chemical reactions

Answer 64

by providing an alternative reaction pathway of lower activation energy

Question 65

why do many transition metals act as catalysts

Answer 65

due to their ability to exist in a variety of different oxidation states

Question 66

how do ligands form complexes with metal atoms

Answer 66

donate pairs of electrons

Question 67

homogeneous

Answer 67

same state as reactants, change their oxidation allowing formation of intermediate complexes, then reverts back to its original state

Question 68

heterogeneous

Answer 68

different state as reactants, work by absorption of the reactant molecules to their active sites, presence of unpaired d-electron allow activated complex to form providing an alternative pathway and activation energy

Question 69

how do transition metals act as catalysts

Answer 69

unpaired d electrons (donating and accepting electrons)

Question 70

how do unpaired electrons arise in H20 easier than in CN-

Answer 70

H2O has a smaller splitting energy so it is easier for electrons to jump up to the higher energy d orbitals

Question 71

why are transition metals coloured

Answer 71

light is absorbed when electrons in lower energy d orbitals are promoted in a d-d transition, if the energy absorbed is visible light then it will be coloured

Question 72

changing the ligand in a complex can

Answer 72

change the colour

Question 73

a complex may be colourless because

Answer 73

it was in the UV spectrum, it has a full d subshell

Question 74

what causes d orbital splitting

Answer 74

lone pairs of electrons in the ligand