Transition and Inner Transition Elements

Vocabulary flashcards focusing on electronic configurations, periodic trends, shielding effects, metallic properties, and oxidation states of transition elements based on lecture notes.

Transition Elements

d-block elements appearing in groups 3 to 12 of the periodic table whose atoms or cations possess an incomplete d-subshell, displaying variable oxidation numbers and having their last electron enter a d-subshell.

General Electronic Configuration of Transition Elements

The general valence electron configuration represented as $(n-1)d^{1-10} ns^{1-2}$.

3d Series

The first transition series consisting of elements from Scandium ($Z=21$) to Zinc ($Z=30$).

4d Series

The second transition series consisting of elements from Yttrium ($Z=39$) to Cadmium ($Z=48$).

5d Series

The third transition series consisting of elements from Lanthanum ($Z=57$) to Mercury ($Z=80$), excluding elements from Cerium to Lutetium.

6d Series

The fourth transition series consisting of elements from Actinium to Copernicium, excluding elements from Thorium to Lawrencium.

Electronic Configuration of Chromium

$[\text{Ar}] freeze 3d^5 4s^1$ (written as $[\text{Ar}] 3d^5 4s^1$), which is an exception due to the stability of a half-filled 3d subshell.

Electronic Configuration of Copper

$[\text{Ar}] 3d^{10} 4s^1$, which is an exception due to the stability of a completely filled 3d subshell.

Cation Formation in First Transition Series

Loss of one 4s electron forms an $M^+$ ion, loss of two 4s electrons gives an $M^{2+}$ ion, and loss of unpaired 3d and 4s electrons forms $M^{3+}$ and $M^{4+}$ ions.

Bonding Behavior across Oxidation States

Transition elements form ionic compounds in lower oxidation states and covalent compounds in higher oxidation states.

Shielding Effect of 4f-Orbitals

A poor shielding effect exerted on valence electrons due to the peculiar diffused state of filled 4f-orbitals in elements of the third transition series.

Ionization Enthalpy of Third Transition Series

Ionization enthalpies that are much higher than those of the first and second transition series because poor 4f shielding causes valence electrons to experience greater nuclear attraction.

Metallic Character of Transition Elements

Property arising from low ionization enthalpies and vacant d-orbitals in the outermost shell, which favor the formation of metallic bonds.

Ambient Temperature Metallic Structure Exceptions

Zinc ($\text{Zn}$), Cadmium ($\text{Cd}$), Mercury ($\text{Hg}$), and Manganese ($\text{Mn}$), which are exceptions to having typical metallic structures at ambient temperature.

Atomic Radii Trend in Transition Series

A gradual decrease in atomic radii from left to right across a series caused by nuclear charge increasing by one unit at a time while d-electrons offer smaller screening effect.

Screening Effect of d-Orbitals

A smaller screening effect provided by d-electrons because d-orbitals in an atom are less penetrating or more diffused, resulting in an increased effective nuclear charge along a transition series.

Ionic Radii Trend

A gradual decrease in ionic radii observed with an increase in nuclear charge for elements in the same oxidation state, following the same trend as atomic radii.

Ionization Enthalpy

The energy needed to remove an electron from the outermost shell of an atom.

Electropositivity of Transition Elements

Transition elements are less electropositive than group 1 and 2 elements, with ionization enthalpies that are intermediate between s-block and p-block elements.