When an atom of sodium reacts with an atom of chlorine to form sodium chloride, each sodium atom:

Correct option is C

Correct option: (c), loses one electron.

When an atom of sodium (Na) reacts with an atom of chlorine (Cl) to form sodium chloride (NaCl), each sodium atom:

• ​Loses one electron to become a positively charged ion (Na⁺).
  

​This is because sodium, which has one electron in its outermost shell, wants to achieve a stable electron configuration (like the nearest noble gas, neon). By losing this outer electron, sodium becomes a cation (Na⁺).

The chlorine atom, on the other hand, gains the electron that sodium loses, becoming a negatively charged ion (Cl⁻). These oppositely charged ions (Na⁺ and Cl⁻) are held together by an ionic bond, forming the compound sodium chloride (NaCl).