Answer:
1. NaCl .
Step-by-step explanation:
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In this case, it is necessary to keep in mind that just ionic compounds are able to conduct electricity and therefore, the more ionic the compound is, the more electricity it conducts. In such a way, we may be able to predict how ionic these compounds are, considering that the electronegativity increases from bottom to top and from left to right.
1. NaCl: this is the most ionic compound since it is at the leftmost group and bonded with chlorine, so this is the most conductive one.
2. Mg(CIO3)2: Mg is bonded to O, not to Cl, which makes the compound ionic but not as ionic as NaCl.
3. NiCl: Ni is more electronegative than Na and Mg, so even when this is ionic, it is not as ionic as NaCl.
4. CaCl2: This is similar to NaCl but since Ca is in group 2A, it is more electronegative than Na, which makes CaCl2 conductive but not as much as NaCl.
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