Questions and Answers
Which series of transition elements involves the filling of 3d-orbitals?
What is the reason for the gradual decrease in electropositive character of transition metals across a period?
What property allows transition metals to exhibit a variety of oxidation states?
Why do transition metals often form colored compounds?
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Which block of elements are referred to as inner-transition elements?
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What trend is observed in the melting points of transition metals across a series?
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What causes the progressive decrease in the ionic radii of transition metals in a given series with increasing atomic number?
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Why do most transition metals react with mineral acids to liberate H2 gas?
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What is the primary reason that transition metals can form a large number of alloys?
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Which oxidation state is most commonly observed in actinides?
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What characteristic is true for the oxides of transition metals in higher oxidation states?
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What is the general electronic configuration of lanthanides?
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Which property do the majority of lanthanide ions exhibit due to unpaired electrons?
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What happens to the atomic size of actinides as you move across the series?
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Which statement is correct regarding the compounds of lanthanides?
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What phenomenon is referred to as lanthanoid contraction?
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Study Notes
Transition Elements
- Located between s-block and p-block elements in the periodic table (groups 2 to 13).
- Comprise three transition series, each containing ten elements.
First Transition Series
- Involves filling of 3d-orbitals, starting from scandium (Z = 21) to zinc (Z = 30).
Third Transition Series
- 5d-orbitals are filled, beginning with lanthanum (Z = 57), followed by lanthanides (14 elements filling 4f-orbitals) and concluding with elements from hafnium (Z = 72) to mercury (Z = 80).
Inner-Transition Elements
- F-block elements are classified as inner-transition elements.
Properties of Transition Metals
- Metallic characteristics: good conductors of heat and electricity.
- Electropositive character decreases across a period.
- Metals are hard with high densities and melting/boiling points due to strong metallic bonds.
Behavior of Metallic Bonds
- Melting point initially rises to a maximum before declining towards the end of the series.
- The strength of metallic bonds correlates with the number of half-filled d-orbitals.
Ions and Ionization Energy
- Ionic radii decrease with increasing atomic number, attributed to poor shielding by d-electrons.
- Ionization energies are higher than s-block but lower than p-block elements, generally increasing left to right across the series.
Oxidation States and Reactivity
- Transition metals exhibit multiple oxidation states due to ns and (n-1)d electrons participating in bonding.
- Most transition metals are sufficiently electropositive, reacting with mineral acids to release hydrogen gas.
Common Characteristics
- Transition metals and many compounds are paramagnetic.
- Formation of colored compounds is typical, due to d-d electron transitions absorbed from visible light.
Complex Formation
- Ability to form complexes due to small, highly charged ions and vacant d-orbitals.
Catalytic Properties
- Many transition metals and their compounds act as catalysts in various reactions.
Interstitial Compounds and Alloys
- Transition metals form numerous interstitial compounds.
- A significant variety of alloys is formed, as atoms can easily substitute positions in metal lattices.
Oxide Properties
- Oxides of transition metals in lower oxidation states typically exhibit basic characteristics, whereas higher oxidation states show amphoteric or acidic properties.
F-Block Elements
- Divided into lanthanides (4f-orbitals) and actinides (5f-orbitals), based on the last electron's entry.
Lanthanides
- General electronic configuration: [Xe] 4f1-14 5d0-1 6s2.
- Silvery-white, malleable, and ductile with low tensile strength.
- Generally exhibit +3 oxidation state, with some showing +2 (Eu2+) and +4 (Ce4+).
- Exhibit paramagnetism due to unpaired electrons; exceptions occur with no unpaired electrons.
Actinides
- General electronic configuration: [Rn] 5f0-14 6d0-1 7s2.
- All are silvery-white metals with moderately high melting points.
- Exhibit several oxidation states; +4 is preferred.
Lanthanoid Contraction
- A gradual decrease in atomic size across the first f-transition element series.
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Description
Test your knowledge on transition elements with this quiz focused on their properties, series, and classifications. Explore the differences between first and third transition series as well as inner-transition elements. Perfect for students studying the periodic table and metallic bonds.
