* Sodium (Na) has a positive charge because it loses one electron, becoming Na⁺.

* Chlorine (Cl) has a negative charge because it gains one electron, becoming Cl⁻.

When sodium and chlorine combine, they form sodium chloride (NaCl), commonly known as table salt. The positive sodium ion (Na⁺) and the negative chloride ion (Cl⁻) attract each other due to their opposite charges, forming a neutral compound.

Therefore, it's not the charge on the sodium that becomes negative, but rather the chlorine that gains a negative charge.