Answer:
An element in Group 16 (oxygen, sulfur, selenium, etc.)
Step-by-step explanation:
Sodium (Na) typically forms the cation Na⁺ during ionic bonding. If the overall charge of the compound is neutral (0), and there are two Na⁺ ions present (+1 + (+1) = +2), the element serving as the anion must have a -2 charge (+2 + (-2) = 0). Elements in group/column 16 have a -2 charge when ionized.