Answer:
D. a bond between two atoms that have equal electronegativities
Step-by-step explanation:
Covalent bonds involve 2 atoms sharing electrons.
Covalent Bonds
There are 3 types of bonds: metallic, ionic, and covalent. Metallic bonds occur between 2 metals that exist in a "sea of electrons." Ionic bonds have high electronegativity differences and occur between a metal and a nonmetal. Finally, as stated above, covalent bonds occur when 2 atoms share their electrons. Covalent bonds usually occur between two nonmetals. However, there are 2 types of covalent bonds: polar and nonpolar.
Nonpolar Bonds
Both polar and nonpolar bonds involve the sharing of electrons; however, polar bonds share electrons unequally. This is caused by an electronegativity difference greater than 0.5. When two atoms have equal electronegativities, they share the electrons equally. This creates a nonpolar bond.