Which atom forms a positive ion?

Which atom forms a positive ion?

• A. Ne
• B. F
• C. Li
• D. Na

Answer: (C)

Forming a positive ion happens when an atom loses electrons, becoming a cation. Lithium fits this idea best here because it has only one electron in its outer shell, so losing that single electron gives it a stable arrangement like helium, resulting in Li+. Neon already has a full outer shell and tends not to lose electrons, so it stays neutral. Fluorine, being a nonmetal, tends to gain an electron to become F− rather than losing one. Sodium also can form a positive ion by losing an electron, but lithium’s single valence electron makes it the clearest and simplest example of forming a positive ion among these options.

Forming a positive ion happens when an atom loses electrons, becoming a cation. Lithium fits this idea best here because it has only one electron in its outer shell, so losing that single electron gives it a stable arrangement like helium, resulting in Li+. Neon already has a full outer shell and tends not to lose electrons, so it stays neutral. Fluorine, being a nonmetal, tends to gain an electron to become F− rather than losing one. Sodium also can form a positive ion by losing an electron, but lithium’s single valence electron makes it the clearest and simplest example of forming a positive ion among these options.