Final answer:
The correct answer is C. Lose, cation, as a positive ion, or cation, forms when an atom loses electrons.
Step-by-step explanation:
The positive ion formed from an atom will result from the atom's tendency to lose electrons. Such ions are called cations, and they are usually formed by metals which are elements that often lose electrons easily. An example of this is sodium, which loses one electron to become Na+, or calcium, which loses two electrons to become Ca2+. In contrast, when an atom gains electrons, it becomes a anion, which is negatively charged. For instance, chlorine gains one electron and becomes Cl− or oxygen which gains two electrons and becomes O2−. Thus, the correct answer to the question 'The positive ion will be formed from an atom that has a tendency to _________ electrons and will usually be a ___________.' is C. Lose, cation.