Which is the best Lewis structure for NaCl? Na : Cl ? Na-Cl: IV. Na I and III are both acceptable
The Correct Answer and Explanation is:
The correct answer is Option I.
Explanation:
Sodium chloride (NaCl) is an ionic compound composed of a sodium ion (Na⁺) and a chloride ion (Cl⁻). Sodium, which has one valence electron, tends to lose that electron to achieve a stable electron configuration resembling that of neon. This loss of an electron turns sodium into a positively charged ion (Na⁺). Chlorine, with seven valence electrons, tends to gain one electron to complete its octet, thus becoming a negatively charged ion (Cl⁻).
The best Lewis structure for NaCl must reflect this complete transfer of an electron from sodium to chlorine, resulting in full charges on both ions and complete octets where applicable.
Looking at the given options:
- Option I correctly shows Na⁺ and Cl⁻, with sodium having no electrons around it (having lost its single valence electron) and chlorine having eight electrons (its original seven plus the one gained from sodium). This accurately represents the ionic nature of NaCl.
- Option II shows a covalent bond between Na and Cl, which is incorrect. NaCl is not covalent but ionic, and thus does not share electrons.
- Option III shows Na and Cl connected with a dash, suggesting a covalent bond, which misrepresents the true nature of the ionic bond.
- Option IV shows an unusual structure with Na still holding onto an electron, which is not consistent with the complete transfer of an electron that occurs in ionic bonding.
Since NaCl forms via the complete transfer of electrons, the structure in Option I best represents this ionic bond. It reflects both the correct charges and electron configurations of each ion, making it the most accurate Lewis structure for NaCl.
