What atom or ion has the electron configuration [Ar]3d10
The Correct Answer and Explanation is:
The electron configuration [Ar] 3d10 corresponds to the Zn2+ ion (zinc ion with a +2 charge).
Here’s why:
- Start with the neutral zinc atom (Zn):
The atomic number of zinc is 30, so its neutral configuration is:
Zn: [Ar]4s23d10\text{Zn: } [Ar] 4s^2 3d^{10}Zn: [Ar]4s23d10
The two electrons in the 4s orbital and the ten electrons in the 3d orbital make up a fully filled electron configuration for zinc. - When zinc loses two electrons to become Zn2+:
Zinc tends to lose its two 4s electrons because 4s orbitals are higher in energy than 3d orbitals. After losing two electrons, the electron configuration of Zn2+ becomes:
Zn2+:[Ar]3d10\text{Zn}^{2+}: [Ar] 3d^{10}Zn2+:[Ar]3d10
Notice that the 4s orbital is now empty, and all 10 electrons remain in the 3d orbital, resulting in a filled 3d subshell. - Electron configuration of Zn2+:
- The [Ar] core represents the same electron configuration as argon (Ar), which is the noble gas preceding zinc.
- The 3d10 part indicates that all 10 electrons fill the 3d orbital, creating a stable, fully filled d-subshell.
- Why does Zn2+ have a [Ar] 3d10 configuration?
Losing two electrons from the 4s orbital results in a more stable electron configuration with a fully occupied 3d subshell. Zinc has a relatively high tendency to form a +2 charge because the 4s electrons are more easily removed than the 3d electrons, leading to a stable configuration for Zn2+.
This electron configuration is typical of transition metal ions, where d-subshells often play a crucial role in defining the chemical properties of the ions.
