To determine which two elements would bond together based on their ionic charges, we need to consider the charges of the elements in the list:
- Potassium (K) is in Group IA (1A) and typically has a +1 charge when it forms ions.
- Calcium (Ca) is in Group IIA (2A) and typically has a +2 charge when it forms ions.
- Iodine (I) is in Group VIIA (7A) and typically has a -1 charge when it forms ions.
- Neon (Ne) is in Group VIIIA (8A) and is a noble gas, which generally does not form ions.
For bonding to occur through ionic bonding, a positive ion must bond with a negative ion.
- Potassium (K) with a +1 charge can bond with iodine (I) with a -1 charge.
- Calcium (Ca) with a +2 charge would bond with two iodine (I) with -1 charges, but it doesn't bond directly with neon since neon does not form ions.
Based on this analysis, the correct answer is:
potassium and iodine.