Question

multiple choice question
when nacl is formed, ______.
○ a chlorine atom loses an electron, while a sodium atom gains an electron
○ a sodium and a chlorine atom both gain an electron
○ a sodium and a chlorine atom both lose an electron
○ a sodium atom loses an electron, while a chlorine atom gains an electron

Explanation:

Sodium (Na) is a group 1 metal with 1 valence electron, so it readily loses this electron to form a positively charged ion ($\text{Na}^+$). Chlorine (Cl) is a group 17 nonmetal with 7 valence electrons, so it gains 1 electron to form a negatively charged ion ($\text{Cl}^-$). These ions attract to form ionic NaCl.

Answer:

a sodium atom loses an electron, while a chlorine atom gains an electron