Final answer:
The correct notation for a calcium ion with a full octet is Ca²+, which represents a calcium cation with a 2+ charge.
Step-by-step explanation:
The correct notation for a calcium ion with a full outer shell is Ca²+. Calcium typically loses two electrons to achieve a stable octet configuration, resulting in a cation with a +2 charge. A calcium atom has an atomic number of 20 and an electron configuration of [Ar]4s². When it loses two electrons (the 4s² electrons), it achieves the electron configuration of Argon, which is a noble gas with a full octet. The resulting calcium ion has a 2+ charge because it has 20 protons (positively charged) and only 18 electrons (negatively charged), making it a calcium cation represented as Ca²+.