Question

what is this sodium atom known as?
loses outer
electron
a. isomer
b. isotope
c. anion
d. ion

Explanation:

• Option A: Isomers are related to molecular structure (same formula, different structure) in chemistry, not atomic charge changes. So A is incorrect.
• Option B: Isotopes are atoms of the same element with different numbers of neutrons, not related to electron loss/gain. So B is incorrect.
• Option C: Anions are negatively charged ions (gain electrons), but sodium here loses an electron to become positive. So C is incorrect.
• Option D: An ion is an atom (or group of atoms) with a net electric charge due to loss or gain of electrons. Sodium (Na) loses an electron to become \( \text{Na}^+ \), which is an ion. So D is correct.

Answer:

D. Ion