To determine which two elements would bond together based on their ionic charges, we need to identify the likely charges of the elements listed:
- Potassium (K) is in Group IA and typically has a charge of +1 when it forms an ion (K⁺).
- Calcium (Ca) is in Group IIA and typically has a charge of +2 when it forms an ion (Ca²⁺).
- Iodine (I) is in Group VIIA and typically has a charge of -1 when it forms an ion (I⁻).
- Neon (Ne) is in Group VIIIA and is a noble gas, meaning it does not typically form ionic bonds because it is already stable and does not gain or lose electrons.
To form an ionic bond, one element must have a positive charge and the other must have a negative charge. Therefore:
- Calcium (Ca²⁺) could bond with two Iodine (I⁻) ions to form CaI₂.
- Potassium (K⁺) can bond with one Iodine (I⁻) ion to form KI.
The elements that would bond together based on their ionic charges from the provided list are calcium and iodine.
Given the options you presented, the correct answer is potassium and iodine (K⁺ + I⁻).