Chemistry Transition Elements Quiz

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.