period 3

Question 1

transition metal element definition

Answer 1

one which forms at least one stable ion with a partially filled d subshell

Question 2

Chromium electron configuration

Answer 2

Question 3

Copper electron configuration

Answer 3

Question 4

transition elements key feautures

Answer 4

3CV
-complex ions
-coloured ions
-catalytic properties
-variable oxidation states

Question 5

ligand

Answer 5

•ion or molecule with a lone pair of electrons

•which can form a coordinate bond

•with a transition metal ion

Question 6

bidentate ligand

Answer 6

has two atoms that each donate a lone pair of electrons

Question 7

complex ion

Answer 7

central metal atom/ion

surrouded by ligands

Question 8

chelate effect

Answer 8

•when a monodentate ligand is substituted by a bidentate/mutidentate ligand

•and there is a large increase in entropy

Question 9

why reaction is thermodynamically favourable?

Answer 9

ΔG = ΔH –TΔS

-ΔH is negligible
-makes and breaks the same number of bonds
-makes and breaks bonds that have similar enthalpies

-increase in entropy
-increase in particles in solution

-ΔG is negative (for forward reaction)
-because TΔS > ΔH

Question 10

what is porphyrin

Answer 10

forms 4 bonds to a ring system called porphyrin

(central Fe2+ ion which has a coordination number of 6)

Question 11

haemoglobin

Answer 11

-4 coordinate bonds between Fe2+ and N atoms in the haem structure
-1 coordinate bond between Fe2+ and protein globin
-1 coordinate bond between Fe2+ and O2 molecule

Question 12

why CO is toxic?

Answer 12

-CO bonds more strongly to Fe2+ in haemoglobin
-this prevents O2 from binding to Fe2+
-causing suffocation

Question 13

why can haemoglobin transport O2?

Answer 13

O2 forms a coordinate bond to Fe2+ in Hb enabling O2 to be transported in blood

Question 14

when do optical isomers occur in transition metal ions?

Answer 14

•when octahedral complex

•has at least 2 bidentate ligands

•cis structure will have optical isomers

Question 15

in light spectrum which 3 colours are low energy and which are high?

Answer 15

ROY=low energy
BIV=high energy

Question 16

whats ground state

Answer 16

•in pure transition metal atoms

•all d-orbitals are of equal energy

Question 17

frequency of light equation

Answer 17

ΔE =h x f

f=c÷λ

h= planck constant
c= speed of light
λ = wavelenght of light
f= frequency of light (Hz)

Question 18

why Cu2+ blue?

Answer 18

-absorbs visible red light
-electrons excited to a higher energy d-orbital
-blue visible light reflected/transmitted

Question 19

When transition element compound has a large energy change between d sub shells

Answer 19

Blue is absorbed (high energy light)
Red is transmitted

Question 20

When transition element compound has a small energy change between d sub shells

Answer 20

Red is absorbed (low energy light)
Blue is transmitted

Question 21

what can alter the colours of a compound

Answer 21

change in:
-ligands
-oxidation state
-coordination number of complex
-(shape of complex)

Question 22

absorbance reading of 1.0

Answer 22

all light passes through sample
And
none is absorbed

Question 23

absorbance reading of 0.5

Answer 23

50% light transmitted
50% light absorbed by compound

Question 24

absorbance reading of 0.0

Answer 24

all light absorbed by.. ““compound”

Question 25

heterogeneous catalyst

Answer 25

catalyst is in a different phase to the reactants

Question 26

homogeneous catalyst

Answer 26

catalyst is in the same phase as reactants

Question 27

colorimetry apparatus

Question 28

describe stages of alternative route **examples you must know**

Answer 28

-making ammonia in haber process catalysed by iron -making H2SO4 catalysed by Vanadium Oxide (V2O5) (manufacturing methanol catalysed by Chromium oxide Cr2O3)

Question 29

heterogeneous catalyst mechanism

Answer 29

-reactants adsorb on the surface of the catalyst on an active site -reaction occurs on the surface of the catalyst -bonds are weakened -products desorb from the surface of catalyst

Question 30

how to make catalyst more efficient

Answer 30

-increase surface area (eg. powder) -spread catalyst over inert support medium

Question 31

what is poisoning

Answer 31

-impurites can block active sites -prevents reactants from adsorbing -purifying the reactants is the best way to prevent poisoning

Question 32

equations for heteregeneous catalyst making ammonia

Answer 32

**N2 + 3H2 ⇌ 2NH3**

Question 33

equations for heteregeneous catalyst making sulfuric acid

Answer 33

SO2 + V2O5 ⇌ SO3 + V2O4 2V2O4 + O2 ⇌ 2V2O5 overall reaction: 2SO2 + O2 ⇌ 2SO3

Question 34

why can transition metal ions act as catalyst why can't a group 1 element act as catalyst?

Answer 34

**they have variable oxidation states** group 1 element only exist in one oxidation state

Question 35

in colorimeter, what affects the amount of absorption

Answer 35

lenght of container the solution is in (cuvette)

Question 36

equations for homogeneous catalyst S2O8^2- and I-