What Is a Covalent Bond?

• French B
• Geography
• German A
• German A Lit
• German ab initio
• German B
• Global Politics
• History
• History (First Exam 2028)
• Mathematics Analysis and Approaches (AA)
• Mathematics Applications & Interpretation (AI)

• Philosophy
• Physics
• Psychology
• Psychology (First Exam 2027)
• Spanish A
• Spanish A Lit
• Spanish ab initio
• Spanish B
• Sports, exercise and health science (SEHS)
• Theory of Knowledge (TOK)
• World Religions

• MYP English Lang & Lit
• MYP Extended Mathematics
• MYP History

• MYP Individuals & Societies
• MYP Integrated Sciences
• MYP Physics

• MYP Standard Mathematics

Atoms can share more than one pair of electrons:

For the same pair of atoms, increasing the number of shared pairs generally makes the bond stronger and shorter.

Sharing is not always equal. A difference in electronegativity produces bond polarity because the bonding electrons are attracted more strongly by one atom. For example, the bond in $\text{HCl}$ is polar, whereas the bond in $\text{Cl}_2$ is non-polar. Molecular polarity then depends on both bond polarity and molecular geometry.

In a coordinate bond, both electrons in the shared pair originate from the same atom. However, the resulting bond is still covalent because the shared pair is attracted to both nuclei.

A common misconception is that a covalent bond is simply “two electrons being shared.” This is incomplete: the bond itself is the electrostatic attraction involving that shared pair and the two nuclei.

Exam technique

For a definition question, state “electrostatic attraction,” “shared pair of electrons,” and “positively charged nuclei.” When drawing a Lewis formula, show every bonding pair clearly and include any lone pairs needed to represent the structure correctly.