Identify the element whose 2+ ion has the ground-state electron configuration [Ar] 3d10.

Verified step by step guidance

1. Step 1: Understand that the given electron configuration [Ar] 3d^{10} represents the electron configuration of a 2+ ion, meaning the element has lost 2 electrons.
2. Step 2: Recognize that the electron configuration [Ar] 3d^{10} corresponds to a filled 3d subshell, which is characteristic of the transition metals.
3. Step 3: Recall that the electron configuration of a neutral atom is determined by adding electrons to the subshells in the order of increasing energy levels, following the Aufbau principle.
4. Step 4: Determine the neutral atom's electron configuration by adding 2 electrons to the given configuration [Ar] 3d^{10}, resulting in [Ar] 3d^{10} 4s^{2}.
5. Step 5: Identify the element with the electron configuration [Ar] 3d^{10} 4s^{2} as Zinc (Zn), which upon losing 2 electrons forms the Zn^{2+} ion with the configuration [Ar] 3d^{10}.