Transition Elements and Iron

- a) The main transition elements:
They are elements of d- block including three series which are located in periods 4, 5 and 6

b) inner transition elements: Include f-block elements. Two series:
Lanthanides: Where sub-level (4f) is frequently filled. It is located in period - 6 after lanthanum; semi-colon; it starts with cerium ₅₈Ce and ends with lutetium (₇₁Lu) and have the electronic structure

- Elements of Lanthanide series are similar in chemical and physical properties because the change in the number of electrons takes place in sub-level (4f) which exist deeply under 6s, 5d energy levels.
- They have oxidation number (+3), since the valence electrons are located in sub-levels (5d¹, 6s²) by which the atom share in the reaction, while (4f) electrons donot take part in chemical reactions.
- Actinides series In which sub-level (5f) is frequently filled with electrons. It is located in period-7 after Actinium. It starts with Thorium (₉₀Th) and ends with Lawransium (₁₀₃Lr). They are radioactive elements as their unstable nuclie. They have electronic structure [Rn] 5 f ^{1 - 14} 6 d¹ 7s².

The transition Element: It is the element in which orbitals of sub-level (d) or (f) are occupied with electrons but not completely filled either in the atomic state or oxide states.
- Coinagemtals (Cu, Ag, Au) are transition metals although orbitals of (d) are filled with electrons. Because in their higher oxidation states contain 9 or 8 electrons in d sublevel.
- ₃₀Zn, ₄₈Cd, ₈₀Hg are non-transition elements because the orbitals of (d) sublevel are completely filled with electrons in their free state or in their higher oxidation states.
- Chromium (₂₄Cr) and copper (₂₉Cu) are anomalous from the expected electronic configuration.

This make the atom has less energy and more stability.
- Iron II is easily oxidized to iron III.
Because iron III is more stable as the 3 d sublevel is half - filled, and it is difficult to reduce Iron III to Iron II for the same reason.
- Mn (II) is difficulty oxidized to Mn III. Because Mn (II) is more stable as the 3 d sublevel is half - filled, while Mn (III) is reduced easily to Mn (II) for the same reason.
- Transition elements atomic radie are nearly constant due to two opposite factors; The first acts to increase the atomic radius, the second acts to decrease the atomic radius. So they are considered representatives for alloys manufacture.
- The densities of transition elements increase with the incresase of atomic number due to the increase of the atomic mass while the atomic radius is nearly constant.
- The transition elements have catalytic activity due to the presence of unpaired electrons in the orbitals of "d" sublevel which can be used in formation of bonds between the reacting molecules and the atoms on the metal surface therfore the concentration of reactants increases on the catalyst surface so the speed of reaction increases.
- Transition elements have high melting and boiling point because they have strong metallic bonds resulting from sharing of both the 4s and 3d electrons.
- Transition elements are considered paramagnetic substances due to the presence of unpaired electrons in orbitals of sublevel (d).
- The magnetic moment is equal to the number of unpaired electrons in (d) sublevel. Such as iron (Fe) the magnetic moment = the moment of (4) unpaired electrons in orbitals of (3d).
- The magnetic moment of zinc = zero. All electrons in (3d) are paired.
- The paramagnetic substance is the substance which is attracted to the magnetic field due to the presence of unpaired electrons in "d" orbitals.
- The diamagnetic substance is the substance which is repelled to the magnetic field due to the presence of electrons paired in all "d" atomic orbtials.
- Atoms or ions of transition elements are coloured due to the incompletly filled orbitals of "d" sub-level (from 1 to 9 electrons)
- Atoms or ions are uncoloured in the following cases:
a- When the orbtials of d^o are empty. Ex: Sc ⁺³
b- When the orbtials of d¹⁰ are completely filled ex: Zn⁺²
c- When the unpaired electrons exist in orbtials of s, p such as in sodium or potassium since the normal light unable to excite s, p electrons.

" Cases of rational stability of atoms and ions
a- If sublevel d^o is empty
b- If sublevel d¹⁰ is completely filled with electrons.
c- If sublevel d⁵ is half filled with electrons.

* Atoms or ions of a transition elements are coloured due to the presence of unpaired electrons in the orbitals of "d" which abosrb the amount of energy [equal to the energy of certain colour] sufficient to be excited and jump to higher energy level.

* Iron Ores:

The suitability of the ore for extraction of iron econmically depends on these factors.
1- The percentage of iron in the ore.
2- The composition of the impurities in the ore.
3- The type and presence of harmful elements mixed with the ore such as (S, P, As).
- Extraction of iron from the ores: it includes three stages.
1- Dressing of iron ore
2- Reduction of the iron ore
3- Production iron.

Dressing of the iron ores: It aimes to
a. Increase of percentage of iron in the resulted ore by separating the impurities from the ore.
b. Improvement of the physical properties of the ore.
- Crushing process: A process of converting the large size of the iron ore to small size to be easily reduced.
- Magnetic separartion: It aimes to separate impuriites from the ore by using a strong magnetic field.

Floating process:
It aims to separate impurities from the ore by carrying the iron ore coated with oil to form froth float on the surface and can be removed easily.

Roasting process:

The Blast Furnace:
Its idea depends on the reduction of Haematite ore by (CO) gas to iron called pig iron
- Coke (C) and CO cycle in the blast furnace:

- The role of lime stone (CaCO₃) in blast furnace.
It decomposes by heat to CaO, CO₂ then CaO combine with impurities oxides to form slage.

Slag:
a mixed of which prevent iron oxidation because it floats on the molten pig iron. It is used in brick industry, cement and road pavements.

Midrex Furnace
Its idea depends on reduction of Haematite ore by using (Co + H₂) to iron called spongy iron.

Natural gas (CH₄) combine with CO₂ and H₂O forming (CO + H₂)

The oxygen converters:
Its idea depneds on blowing of oxygen rapidly under high pressure from the top of the converter oxidizing the impurities to acidic and alkaline oxides which combine together forming the slag. It floats on the surface of molten iron.
- The furnace is lined with dolomite .
It decomposes by heat forming CO₂ and basic oxides which react with acidic oxides of impurities to produce slag.
- Ferromanganese alloy prevents the formation of gas bubbles (O₂) steel since manganese combines with oxygen in steel.
Characteristies given to iron by the increase of carbon ratio are:
1- Its hardness increase
2- The melting point decreases.
3- It bears high pressure but not shocks.
4- It can't be hammereor pulled.

- Carbon in iron is either found separated in the intermolecular distances (inter stitional alloy), or combined in the form of Fe₃C (inter metalic alloy)

-

-

Due to formation of non-porous oxide layer the metal becomes chemically inactive.

FeCl₃ is formed because (Cl₂) is oxidizing agent.

Iron oxides:
a) Iron II oxide

Iron II oxide is basic oxide because it reacts with acids forming salt and water.

- Reactions:
Iron III oxide is basic because it reacts with acids giving salt and water. Its reactions take place with hot conc. acids because the oxidation number of iron in iron III oxide is (+3), ie. It is rationally stable as it contains 5 electrons in orbital 3d.

C) Magnetic Iron oxide Fe₃O₄
* Preparation:

Reactions:
It reacts as a complex oxide that gives two kind of salts.

GR: Magnetic iron oxide reacts with conc. acids to give two kinds of salts.

Detection of Iron (II) and iron (III) cations:
1) Iron (II) cations Fe²⁺:

2) Iron (III) cation Fe³⁺:

QUESTIONS and ANSWERS 1:

A. Give reasons for:

1- Scandium has limited uses.

1- Because it is not abundant element in the earth's crust.

2- Titanium is prefered in the manufacture of rockets and super sonic air- crafts.

2- Because it can keep strength at high pressure and temprature.

3- Vanadium is used in the manufacture of steel.

3- Because it gives the steel hardness and corrosion resistance.

4- Vanadium is used in the manufacture of car springs.

4- Because it has correosion resistance and not rust.

5- Chromium is highly reactive but it resist the effect of atmosphere.

5- Due to the formation of non- porous oxide layer on its surface which prevent farther reaction with oxygen in the air.

6- Chromium is used to plate other metals.

6- To resist corrosion and make them more attractive.

7- Manganese is used in the production of steel.

7- Because it reacts with oxygen during production process to prevent the formation of bubbles in steel during cooling.

8- Cobalt II chloride is used in the manufacture of secret ink.

8- Because aqueous solution of cobalt II chloride has a pale pink colour which does not appear in writing, then changing to deep blue colour on dehydration by heating therefore the writing appears:

9- Anhydrous cobalt II chloride is used in atmospheric prediction.

9- Because a certain paper are covered with blue cobalt II chloride when turned to pale pink, this indicate that the increase in relative humidaty in air and possibility of raining.

10- Nickel is used in plating metals.

10- To protect them from oxidation and corrosion and to give them a shiny coating.

11- Caustic soda and liquid hydrogen flouride are kept or stored in containers made of nickel.

11- Due to its resistance to corrosion and it is not affected by them.

12- Chromium and copper are anomalous (abonormal) - in their electronic configuration than the expect one.

12- In case of cromium one electron is transfered from (4S) sublevel to 3d sublevel so the sublevels (4S) and (3d) become half filled. This makes the atom has less energy and more stable.

- In case of copper
one electron is transfered from (4S) sublevel to (3d) sublevel so the sublevel (4s) become half filled and the sublevel (3d) become complete filled, this makes the atom has less energy and more stable

13- Iron II is easily oxidized to iron III while Mn II is not easily oxidized to Mn III.

13- Because iron III is more stable than iron II, 3d sublevel is half filled with electrons

While Mn II is more stable than Mn III because 3d sublevel in Mn II is half filled with electrons therefore Mn II difficult to oxidizied to Mn III.

14- The elementes of the first transition series loses its (4s) electrons before the (3d) electrons.

14- Because the 4s sublevel is the outermost one therefore on oxidation the atom usually loses (4s) electron first then electrons of (3d).

15- The oxidation number of the 1st series of the transition elements is (2+).

15- Because when they gain energy they will loses two electrons from the sublevel (4s) at first.

16- Scandium can not give oxidations state (2+) but it give the oxidation state (3+) only.

16- Because when the atom gains energy it loses two electrons from the sublevel (4s) then one electron from (3d) sublevel to be more stable as [Ar₁₈].

17- Transition elements are characterized by having variable oxidation states.

17- Because the two sublevels (4s) and (3d) of nearly equal energy and their electrons are lost in sequance when the atom is oxidized.

18- Scandium can not give the oxidation number (4+).

18- Because the amount of energy needed to obtain this ion is greater due to the breaking of complete energy level.

19- The coinage metals which are are considered as transition although the orbitals of (d) sublevel are completely filled with electrons.

19- Because in their higher oxidation states contain (9) or (8) electron in (d) sublevel.

20- Tranisition elementrs used in the manufacture of alloys.

20- Because these elements have nearly equal atomic radius and give desired properties when they form alloys.

21- It is difficult to oxidize the elements of the end of the transition series.

21- Because their outer most shell are completely filled with electrons so they have a stable electronic configuration

22- are non transition elements.

22- Because the orbitals of (d) sublevel are completely filled with electrons in their free states or in their higher oxidation states.

23- The densities of transition elements increase with the increase of atomic number.

23- Due to the increase of the atomic mass while the atomic radius is nearly constant.

24- The transition elements have high melting and boiling point.

24- Because they have strong metallic bonds, resulting from sharing of both the (4s) and (3d) electrons.

25- The transition elements are paramagnetic elements.

25- Due to the presence of unpaired electrons in the orbitals of (d) sublevel. example:

26- Ions of non transition elements are colourless.

26- Because the orbitlas of the (d) sublevel are empty or completely filled with electrons. So, they can absorb all colour if light or reflect them.

27- The transition elements have a catalytic activity.

27- Due to the presence of unpaired electrons in the orbitals of (d) sublevel which can be used in the formation of bonds between the reactants molecules and the atoms of the metal surface therefore the concentration of the reactants molecules increase so the speed of the reaction increase.

28- When iron reacts with chlorine iron (III) chloride is formed and not iron (II) chloride.

28- Because chlorine act as oxidizing agent, helps in formation of FeCl₃ and prevent formation of FeCl₂
.

29- When iron reacts with diluted acids iron II salts are formed.

29- Due to the evolution of hydrogen gas which act as reducing agent. reduces FeCl₃ into FeCl₂

.

30- Iron magnetic oxide react with conc. acids to give two kind of salts.

30- Because this kind of oxide react as two oxides (i.e) react as FeO and

31- When iron II oxalate in heated strongly FeO is formed and not .

31- Due to the presence of CO gas which act as reducing agent, prevents formation of Fe₂O₃

32- When iron II oxalate is formed a black ppt. is formed

32- Due to the formation of a black iron II oxide (FeO)

33- When green vitroil is heated strongly its colour is changed from green to brick red colour.

33- Due to the formation of iron III oxide (Haematite) which has a brick red colour

B- Write the scientific expression for each of the following:

1- A process of heating iron ores in air for expelting humidity and before its reduction in the blast furnance.

1- Roasting process.

2- Elements that have all their electrons in paired.

2- Diamagnetic elements.

3- A process in which purification of iron ores takes place by adding water and oil and passing strong air.

3- Air flotation process.

4- Elements that have partially filled (f) sublevel.

4- Inner transition elements.

5- Elements that have partially filled (d) sublevel.

5- Main transition elements.

6- Elements in which the (d) or (f) sublevels are one of their oxidation states.

6- the transition elements.

7- A process of converting the large size of the iron are to small sized suitable for reduction process.

7- Crushing process.

8- A process of converting of the fine particles of the iron ore to a large particles suitable for reduction process.

8- Sintering process.

9- A substance that is attracted to the magnet due to the presence of unpaired electrons in (d) sublevel.

9- paramagnetic substance.

10- A substance that is repelled with the magnet due to the presence of all its electrons in paired state.

10- Diamganatic substance.

11- A mixture of two metals or more in a certain ratio.

11- Alloys.

E. Choose the correct answer:

1- Iron II oxide can be obtained by:
a- Heating iron II oxalate in absence of air
b- Heating iron II sulphate
c- Heating iron III oxide in absence of air.
d- heating iron III sulphate.

1- a: Heating iron II oxalate in absence of air.

2- Element has electronic configuration its maximum oxidation number is:
a- (7+), b- (5+), c- (3+), d- (2+)

1-a: (7+)

3- On heating green vitroil crystals strongly, the following observation are noted.
a- green vitroil loses its water of crystallization only.
b- Iron III oxide is formed.
c- acidic gases are evolved.
d- all previous.

3-d: all previous

4- On passing steam over red hot iron we obtain
a- iron III oxide b- Iron II oxide
c- Magnetic iron oxide d- a and b

4-c: Magnetic iron oxide

5- Substitutional alloys are formed of elements having:
a- The same diameter
b- The same crystalline structure c- The same chemical properties d- (a), (b) and (c)

5-d: The same diameter, the same crystalline structure, the same chemical properties

6- Element has the atomic number (29) its electronic configuration is:
a- b- c- e-

6-b:

7- Element has the electronic structure the element is:
a- Paramagnetic in its maximum oxidation states.
b- Dimagnetic in its atomic state.
c- Paramagnetic when its oxidation number is (4).
d- Coloured in its maximum oxidations states.

7-b: Dimagnetic in its atomic state.

8- Elements has the electronic configuration the element is:
a- A main transition element
b- An inner transition element
c- One of lanthanide series d- one of actenide series

8-a: A main transtion element

9- Element has the electronic configuration the element has
a- more than one oxidation state
b- catalytic activity
c- coloured compounds
d- a, b and c

9-d: more than one oxidation state, catalytic activity, coloured compounds

10- Element has the electronic configuration the element belongs to
a- f block elements
b- d-block elements
c- Representative elements
d- d- block elements

10-a: f block elements

C. Complete the following:

1-

1-

2- In the oxygen converter the charge is...............

2- Molten big iron

3-................. is used in the manufactor of secret ink whereas.......... is used in the manufacture of rockets and aeroplanes.

3- anhydrous cobalt II chloride - Tetanium

4- When iron fillings are heated strongly in air.............. is formed which reacts with............. to form two types of salts.

4- iron magnetic oxide - conc. acids

5- When iron is heated with sulphur.............. is formed which reacts with sulphuric acid giving.................. gas turns a paper wet with.............. to a black.

5-

6- When iron reacts with conc. heated ...............,...................,............. and................ are formed.

6-

7-

7-

8-

8-

9-

9-

10-

10-

D. Put () or () and correct the wrong one.

1- Chromium metal resists the action of atmospheric effects although it is chemically active.

1- ()

2- The anhydrous cobalt II chloride is used in atmospheric predictions because the humidity turns its colour from pale pink to blue.

2- () turns the colour from blue to pale pink.

3- Copper and gold form together a substitutional alloy.

3- ()

4- Compounds of iron III are more stable than compounds of iron II because the latter are easily oxidized.

4- ()

5- On strong heating of green vitroil two forms of sulphur oxides are formed.

5-

6- Vanadium ion is coloured.

6- () colourless

7- On passing chlorine gas on hot iron, iron II chloride is formed.

7- ()

8- In medrix furnace carbon monoxide gas can be used as reducing agent.

8- () mixture of CO and

9- When iron fillings reacts with sulphur iron (III) sulphide is formed.

9- ()iron (II) sulphide

10- Iron magnetic oxide reacts with dil. acids to form iron (II) salts and water.

10- () iron (II) and iron (III) slats and water.

TEST 1 ON CH.5:

1 - Element has the electronic configuration [Xe] 4f

a main transition element
an inner transition element
one of lanthanide series
one of actinide series

2 - The anhydrous cobalt II chloride is used in atmos

True
False

3 - When Iron react with dil H₂ SO₄

_{Hydrogen gas
Nitrogen gas
Oxygen gas}

4 - When Iron react with chlorine.............. is fo

Iron III chloride
Iron II chloride
Iron tetrachloride

5 - Compounds of iron III are more stable than compou

True
False

6 - On strong heating of green vitroil two forms of i

True
False

7 - On passing steam over red hot iron we obtain

Magnetic iron oxide
iron III oxide
Iron II oxide

8 - On passing chlorine gas on hot iron, iron II chlor

True
False

9 - Substitutional alloys are formed from elements hav

The same diameter, crystalline structure, melting
the same diameter and crystalline structure
the same melting points
the same chemical properties

10 - On heating green vitroil crystals strongly, the fo

all choices
green vitroil loses its water of crystallization
Iron III oxide is formed
acidic gases are evolved

11 - When green vertial is heated strongly its colour i

brick red
yellow
black

12 - Element has the atomic number (29) its electronic

[Ar] &nb
[Ar] &n
[Ar] &n
[Kr] &nb

13 - Element has the electronic configuration [Ar] &nbs

more than one oxidation state, catalytic activity,
more than one oxidation state
catalytic activity and colourless compounds
coloured compounds

14 - Elements has the electronic configuration [Xe] 4f<

f-block elements
d-block elements
represntative elements
s-block elements

15 - When iron fillings reacts with sulphur iron III su

True
False

16 - Iron II oxide can be obtained by:

Heating iron II oxalate
Heating iron II sulphate
Heating iron III oxide in absence of air.

17 - In blast furnace carbon monoide gas can be used

True
False

18 - When iron II oxalate is heated in absence of air a

iron II oxide
iron magnetic oxide
iron III oxide

19 - Element has the electronic configuration [kr] &nbs

diamagnetic in its atomic state
paramagnetic in its maximum oxidation state
paramagnetic when its oxidation number is (2+)
coloured in its maximum oxidation states

20 - Iron magnetic oxide reacts with dil. acids to form

True
False

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