Electron Configurations of Transition Metals

Electron Configurations of Transition Metals

Overview of Transition Metals in the Periodic Table

The transition metals occupy the d-block (Groups 3–12) of the periodic table. Their electron configurations are characterized by the filling of d orbitals, which leads to unique chemical and physical properties.

• Location: d-block, Groups 3–12

• Electron Filling Order: For cations, electrons are lost first from the highest principal quantum number (n) shell, typically the s orbital, before the d orbital.

Example: The periodic table section highlights the d-block and shows the order of filling for transition metals.

Writing Electron Configurations for Transition Metals

Electron configurations for transition metals follow the Aufbau principle, Hund's rule, and the Pauli exclusion principle. For neutral atoms, electrons fill the lowest energy orbitals first. For cations, electrons are removed from the highest n value orbital first.

• Neutral Atom Example (Titanium, Ti): Atomic number 22

• Electron configuration: $[Ar] \, 4s^2 \, 3d^2$

• Cation Example (Ti2+): Remove electrons from 4s before 3d

• Electron configuration: $[Ar] \, 3d^2$

Condensed Electron Configuration Example

Condensed electron configurations use the noble gas core to simplify notation.

• Example: Vanadium (V), V3+

• Atomic number: 23

• Neutral atom: $[Ar] \, 4s^2 \, 3d^3$

• V3+: Remove three electrons (first from 4s, then from 3d)

• Electron configuration: $[Ar] \, 3d^2$

Practice Problems

• Write the electron configuration for an ion of Tungsten (W):

• W: $[Xe] \, 6s^2 \, 4f^{14} \, 5d^4$

• Determine electron configuration for the ion of Cd in cadmium sulfate (CdSO4):

• Cd2+: $[Kr] \, 4d^{10}$

Key Concepts and Definitions

• Transition Metal: An element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell.

• Electron Configuration: The arrangement of electrons in an atom or ion, described by principal quantum number (n), subshell (s, p, d, f), and number of electrons in each subshell.

• Cation Formation: Electrons are removed first from the highest n value orbital (usually s before d).

Table: Electron Configurations of Selected Transition Metals and Their Common Ions

Element	Atomic Number	Neutral Atom Configuration	Common Ion	Ion Configuration
Titanium (Ti)	22	$[Ar] \, 4s^2 \, 3d^2$	Ti2+	$[Ar] \, 3d^2$
Vanadium (V)	23	$[Ar] \, 4s^2 \, 3d^3$	V3+	$[Ar] \, 3d^2$
Tungsten (W)	74	$[Xe] \, 6s^2 \, 4f^{14} \, 5d^4$	W2+	$[Xe] \, 4f^{14} \, 5d^4$
Cadmium (Cd)	48	$[Kr] \, 5s^2 \, 4d^{10}$	Cd2+	$[Kr] \, 4d^{10}$

Additional info: The above table includes common ions and their electron configurations, which are important for understanding the chemical behavior of transition metals in compounds.