Final answer:
The ion with a +2 charge and the electron configuration [He]2s²2p⁶ is Magnesium cation, represented by the chemical symbol Mg²+.
Step-by-step explanation:
The question asks for the chemical symbol of an atomic cation with a +2 charge and the electron configuration of [He]2s²2p⁶. We can deduce the identity of the ion by considering that its electron configuration corresponds to having 10 electrons in total, which is the same as the noble gas Neon (Ne).
Therefore, the element must come from the next period (since it's a cation and needs to lose electrons) and have two more protons than Neon, which has 10 protons.
This leads us to Magnesium (Mg), which has 12 protons. When Mg loses two electrons, it achieves the electron configuration of Neon, becoming Mg²+. So, the chemical symbol for the ion is Mg²+.