Choose the atom with the largest atomic radius. ci, s, na, si

Na

Explanation:

Cl, S and Na are all in the same period.

The further left an element is in a row of the periodic table, the larger its atomic radius.

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.