Final answer:
The correct answer is a) Atoms, ions, as sodium atoms lose an electron to become sodium cations, and chlorine atoms gain an electron to become chloride anions, forming sodium chloride.
Step-by-step explanation:
When sodium and chlorine react to form sodium chloride, sodium and chlorine atoms are changed into sodium and chloride ions. Therefore, the correct answer is a) Atoms, ions. Sodium atoms, which are metallic and highly reactive with air and water, lose an electron and become sodium cations with a +1 charge.
Chlorine atoms, which form a toxic yellow-green gas, gain an electron and become chloride anions with a -1 charge. The combination of these ions produces the white, crystalline compound known as sodium chloride, or common table salt, which has entirely different properties from its constituent elements.
While chlorine is poisonous and sodium reacts violently with water, sodium chloride is an essential compound for life and readily dissolves in water.