The copper ion, represented as Cu2+, has lost two electrons compared to its neutral state. Copper (Cu) has an atomic number of 29, which means a neutral copper atom has 29 electrons.
To determine the number of electrons in the Cu2+ ion, we simply subtract the number of lost electrons from the total number of electrons in a neutral copper atom:
29 (total electrons in neutral Cu) – 2 (lost electrons) = 27 electrons.
Therefore, the Cu2+ ion has 27 electrons.