- Highly reactive metals like Na, K, and Al are extracted by electrolysis of their molten salts.
- Aluminium is extracted from bauxite using leaching and electrolysis.
- Cryolite and fluorspar help lower the melting point of alumina during extraction.
- Moderately reactive metals like Zn and Fe are extracted by roasting or calcination, then reduced with carbon or aluminium.
- Less reactive metals like gold and silver are found in the free state and extracted by heating.
Definitions [36]
Define transition elements.
Transition elements are those elements that possess incompletely filled d-orbitals in their ground state or in their ions existing in chemically significant oxidation states.
Define d-block elements.
Elements having incomplete d-subshell or elements that give cations with incomplete d subshell are called d-block elements.
Define calcination.
If an ore is a carbonate or a hydrated oxide, it is heated in the absence of air to a temperature that is high but insufficient to melt the ore. The process is known as calcination.
Define the following term.
Gangue
The impurities (sand, silt, soil, gravel, etc.) present in the ore are called gangue.
Define roasting.
Roasting is the process of heating concentrated ore to a high temperature in the presence of air. The process is usually carried out for sulphide ores.
Define the term:
Slag
The product obtained by the combination of gangue with flux is called slag.
Define the term:
Flux
The substance added to get rid of gangue in the extraction of metal is called flux.
Define the following term.
Mineral
Most of the elements occur in nature as in combined state as minerals. The chemical composition of minerals is fixed.
Define the Ore.
Minerals from which metals can be extracted profitably are known as ores.
If minerals contain a very high percentage of a particular metal and the metal can be profitably extracted from it. These minerals are called ores.
Define transuranium.
Elements with atomic numbers greater than 92 are called Transuranium.
Definition: Calcination
Heating of carbonate ore in limited or no air to remove volatile impurities is called calcination.
Definition: Inner transition elements
The f-block elements placed separately at the bottom of periodic table are called inner transition elements.
Definition: Lanthanoids
The series of 14 elements from atomic number 57 to 71 in which 4f orbitals are progressively filled are called lanthanoids.
Definition: Actinoids
The series of elements from atomic number 89 to 103 in which 5f orbitals are progressively filled are called actinoids.
Definition: Lanthanoid contraction
The gradual decrease in atomic and ionic radii of lanthanoids with increase in atomic number is called lanthanoid contraction.
Definition: Actinoid contraction
The gradual decrease in atomic and ionic radii across the actinoid series is called actinoid contraction.
Definition: Hydrometallurgy
Extraction of metal from aqueous solution of its ore using suitable reducing agent is called hydrometallurgy.
Definition: Magnetic moment
The magnetic strength of a substance due to unpaired electrons is called magnetic moment.
Definition: Transition elements
Elements of d-block having incompletely filled (n–1)d orbitals in their atom or in common oxidation states are called transition elements.
Definition: Oxidation state
The charge acquired by an atom when it loses or gains electrons in a compound is called oxidation state.
Definition: Ionisation enthalpy
The energy required to remove an electron from an isolated gaseous atom is called ionisation enthalpy.
Definition: Paramagnetic substance
Substances that are attracted by an external magnetic field due to presence of unpaired electrons are called paramagnetic.
Definition: Diamagnetic substance
Substances that are repelled by a magnetic field and have all electrons paired are called diamagnetic.
Definition: Alloy
A homogeneous mixture of two or more metals or a metal with a non-metal is called an alloy.
Definition: Ferrous alloys
Alloys containing iron as the main metal are called ferrous alloys.
Definition: Non-ferrous alloys
Alloys that do not contain iron as the main metal are called non-ferrous alloys.
Definition: Interstitial compounds
Compounds formed when small atoms like H, C or N occupy interstitial spaces in the crystal lattice of metals are called interstitial compounds.
Definition: Ionization enthalpy
The energy required to remove an electron from an isolated gaseous atom is called ionization enthalpy.
Definition: Metallurgy
The process of extraction of metals from their ores is called metallurgy.
Definition: Catalyst
A substance that increases the rate of a chemical reaction without being consumed is called a catalyst.
Definition: Mineral
A naturally occurring substance in the earth’s crust containing metal or its compounds is called a mineral.
Definition: Ore
A mineral from which metal can be extracted economically is called an ore.
Definition: Pyrometallurgy
Extraction of metal from ore by heating at high temperature is called pyrometallurgy.
Definition: Electrometallurgy
Extraction of metal by electrolysis of molten compound is called electrometallurgy.
Definition: Oxidising agent
A substance that gains electrons and causes oxidation of another substance is called an oxidising agent.
Definition: Gangue
The unwanted impurities like sand, clay, etc., present in an ore are called gangue.
Key Points
Key Points: Extraction of Metals
Key Points: Oxidation states and physical properties of first transition series elements
- Transition elements show variable oxidation states because they can lose different numbers of 3d and 4s electrons.
- The number of oxidation states increases with the increase in the number of unpaired electrons in the 3d orbitals.
- Manganese shows the maximum number of oxidation states in the first transition series, ranging from +2 to +7.
- All transition elements are metals and generally show typical metallic properties such as hardness, malleability, ductility, and good conductivity of heat and electricity.
- Transition metals have high melting and boiling points and form alloys with other metals; however, zinc, cadmium, and mercury are exceptions in some properties.
Key Points: Properties and Trends of First Transition Series Elements
| Property | General Trend | Reason | Example | Important Note |
|---|---|---|---|---|
| Atomic Radii | Decrease gradually from Sc to Zn | Increase in effective nuclear charge; poor shielding by d-electrons | Sc (164 pm) > Fe (126 pm) | Minor irregular variations occur |
| Ionic Radii | Decrease with increase in oxidation state | Higher nuclear charge pulls electrons closer | Cr²⁺ (82 pm) > Cr³⁺ (62 pm) | M³⁺ ions smaller than M²⁺ |
| Ionisation Enthalpy | Slight overall increase across the series | Gradual increase in nuclear charge | Zn has highest IE₁ (906 kJ/mol) | IE₁ < IE₂ < IE₃ for each element |
| Metallic Character | Strong metallic properties | Low ionisation enthalpy and presence of d-electrons | Fe, Co, Ni | Hard, high melting and boiling points |
| Magnetic Properties | Depends on number of unpaired electrons | μ = √n(n+2) BM (spin-only formula) | Mn²⁺ (5.92 BM) | Zn²⁺ is diamagnetic |
| Colour of Ions | Most ions are coloured | Due to d–d electronic transitions | Cu²⁺ (Blue), Fe³⁺ (Yellow) | d⁰ and d¹⁰ ions are colourless |
| Catalytic & Alloy Formation | Show catalytic activity and form alloys | Variable oxidation states and similar atomic radii | Fe (Haber process), Stainless steel | Widely used in industry |
Key Points: Properties of f-block elements
- f-block elements are similar to d-block elements and involve filling of (n–2)f orbitals. They are placed between (n–1)d and ns block elements in the periodic table.
- Lanthanoids (atomic numbers 57–71) are called rare earth elements, though they are relatively abundant but difficult to separate due to similar chemical properties.
- They are soft, reactive metals with moderate density and high melting and boiling points, resembling alkali and alkaline earth metals in reactivity.
- The most common oxidation state is +3, while some elements also show +2 and +4 oxidation states (e.g., Eu²⁺, Yb²⁺, Ce⁴⁺).
- Lanthanoids show contraction in ionic radii (lanthanoid contraction) and form basic hydroxides; many of their ions are coloured due to electronic transitions.
Key Points: Properties of d block elements
- d-block elements are lustrous, hard, and dense metals with high melting and boiling points and good conductivity.
- They form alloys and show paramagnetism, and most of them act as efficient catalysts.
- They are electropositive and exhibit variable oxidation states, forming coloured salts and complexes.
- They act as good reducing agents and generally form insoluble oxides and hydroxides.
- Some d-block elements are biologically important, such as Fe, Co, Cu, Mo, and Zn.
- Higher oxidation states are more stable in second and third transition series; the maximum oxidation state is +7 in the first row and +8 in the third row.
Important Questions [19]
- Write the general electronic configuration of 3d series.
- Which of the following transition element shows maximum oxidation state?
- Give the classification of alloys with examples.
- The spin only magnetic moment of Cr3+ cation is ______.
- What are interstitial compounds?
- Write the name of the alloy used in the Fischer Tropsch process in the synthesis of gasoline.
- Salts of Ti4+ are colourless. Give reason.
- Calculate spin only magnetic moment of divalent cation of transition metal with atomic number 25.
- The spin only magnetic moment of Mn2+ ion is ______.
- Which alloy is used in the Fischer-Tropsch process in the synthesis of gasoline?
- Write reactions involved in preparation of potassium dichromate from chrome iron ore
- Write the balanced chemical equations when acidified KA2CrA2OA7 reacts with HA2S.
- Define roasting.
- Name the radioactive element in lanthanoids.
- Give the electronic configuration of gadolinium (Z = 64).
- Distinguish between lanthanoid and actinoids.
- Write Four Points of Distinction Between Lanthanoids and Actinoids.
- What is the Position of Actinoids in Periodic Table ?
- Write the atomic numbers of transuranium elements.
Concepts [22]
- Transition and Inner Transition Elements
- Position in the Periodic Table of Transition and Inner Transition Elements
- Electronic Configuration of Transition and Inner Transition Elements
- Oxidation States of First Transition Series
- Physical Properties of First Transition Series
- Trends in Atomic Properties of the First Transition Series
- Preparation of Potassium Permanganate
- Chemical Properties of KMnO4
- Uses of KMnO4
- K2Cr2O7: Preparation of Potassium Dichromate
- Chemical Properties of K2Cr2O7
- Common Properties of d Block Elements
- Basic Principles of Metallurgy > Extraction of Metals
- Inner Transition (f-block) Elements: Lanthanoids and Actinoids
- Properties of f-block Elements
- Properties of Lanthanoids
- Applications of Lanthanoids
- The Actinoids
- Properties of Actinoids
- Applications of Actinoids
- Postactinoid Elements
- Overview of Transition and Inner Transition Elements
