Here's why:

* Electrically neutral molecule: Covalent bonds involve the sharing of electrons, so the molecule as a whole remains electrically neutral.

* Covalent bonds between atoms with similar electronegativity: When atoms have similar electronegativity, they share electrons equally. This means there's no significant difference in electron density around each atom, resulting in a nonpolar bond.

Examples of nonpolar covalent bonds:

* H₂ (Hydrogen gas): Both hydrogen atoms have the same electronegativity.

* Cl₂ (Chlorine gas): Both chlorine atoms have the same electronegativity.

* O₂ (Oxygen gas): Both oxygen atoms have the same electronegativity.

Important Note: While a molecule with nonpolar covalent bonds is generally considered nonpolar, the overall molecular shape also plays a role in determining polarity. For example, CO₂ has two polar covalent bonds but is a linear molecule, making it overall nonpolar.