Final answer:
A sodium atom donates an electron to a bromine atom to form an ionic bond in sodium bromide, similar to the formation of sodium chloride.
Step-by-step explanation:
When an ionic compound forms between sodium (Na) and bromine (Br) atoms, the correct statement is that a sodium atom donates an electron to a bromine atom. In this process, the sodium atom loses one electron to form a positively charged sodium cation (Na+), and the bromine atom gains this electron to form a negatively charged bromide anion (Br-). The electrostatic attraction between the oppositely charged ions forms a strong ionic bond, resulting in a stable ionic compound, such as sodium bromide (NaBr), similar to how sodium chloride (NaCl) is formed.