# What is the electron configuration for Zn2+?

Jun 30, 2016

The electron configuration of $\text{Zn"^(2+)}$ is $\text{1s"^2"2s"^2"2p"^6"3s"^2"3p"^6"3d"^10}$.

#### Explanation:

The atomic number of zinc is 30, which means that all zinc atoms have 30 protons in their nuclei. A neutral atom has equal numbers of protons and electrons, so a neutral atom of zinc would have 30 electrons.

The electron configuration of a neutral zinc atom is $\text{1s"^2"2s"^2"2p"^6"3s"^2"3p"^6"3d"^10"4s"^2}$.

The ${\text{Zn}}^{2 +}$ ion has lost two electrons, which leaves it with 30 protons and 28 electrons. The electron configuration of $\text{Zn"^(2+)}$ is $\text{1s"^2"2s"^2"2p"^6"3s"^2"3p"^6"3d"^10}$.

Zinc is a d-block element, also known as a transition element. For the d-block elements, the outermost s-sublevel has higher energy than the d-sublevel, which is contrary to what the Aufbau diagram indicates.

When d-block elements lose electrons, they lose the highest energy s electrons first, which in the case of zinc are the two 4s electrons. Having eight 3d electrons and two 4s electrons is much less energetically stable than ten 3d electrons and no 4s electrons.