Which of the following is a characteristic of an ionic bond?

a. an element shares electrons with another element.
b. an element loses a proton to another element.
c. an element gains a proton from another element.
d. an element donates an electron to another element.

Option D.

Explanation:

An ionic bond is defined as a chemical bond forms when two oppositely charged ions undergo electrostatic attraction. Ionic bonds always formed between a metal (cation), and a nonmetal (an anion).

Ionic bonds are formed when a cation (metal) donates an electron to anion (nonmetal). for example formation of Sodium Fluoride (NaF), sodium (cation) with atomic number eleven is having one valence electron in its outer orbit and fluoride (anion) with atomic number nine require one atom to complete its orbit, so the sodium atoms transfer one electrons to fluoride and leads to the formation of an ionic compound.

Hence, the correct option is D.

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.