Comparing Ionic and Covalent Bonds

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Chemical Bond Noun

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[kem-i-kuhl bond]

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Chemical Bond

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The force of attraction that holds atoms together within a compound, formed by the interaction of their valence electrons.

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Example: This image shows a water molecule where an oxygen atom shares electrons with two hydrogen atoms, forming strong connections called covalent bonds.

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Valence Electrons Noun

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[vey-luhns ih-lek-trons]

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Valence Electrons

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The electrons located in the outermost shell of an atom that are involved in the formation of chemical bonds.

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Example: This Bohr model of a Sodium atom shows its electron shells. The single electron in the outermost shell is its valence electron, which it loses to form an ionic bond.

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Compound Noun

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[kom-pound]

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Compound

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A substance formed when two or more different chemical elements are chemically bonded together in a fixed ratio.

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Example: This image shows a model of a carbon dioxide (CO₂) molecule, an example of a compound where one carbon atom is chemically bonded to two oxygen atoms.

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Ionic Bond Noun

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[ahy-on-ik bond]

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Ionic Bond

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A chemical bond formed by the electrostatic attraction between oppositely charged ions after the complete transfer of valence electrons.

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Example: A sodium atom transfers one outer electron to a chlorine atom, forming a positive sodium ion and a negative chloride ion that attract each other.

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Covalent Bond Noun

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[koh-vey-luhnt bond]

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Covalent Bond

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A chemical bond that involves the sharing of electron pairs between atoms to achieve a stable electron configuration.

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Example: This diagram shows two hydrogen atoms and one oxygen atom sharing their outer electrons to form stable covalent bonds, creating a water molecule.

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Ion Noun

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[ahy-on]

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Ion

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An atom or molecule that has acquired a net electrical charge by either losing or gaining one or more electrons.

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Example: A neutral sodium atom loses an electron to become a positive ion (Na+), while a neutral chlorine atom gains an electron to become a negative ion (Cl-).

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Cation Noun

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[kat-ahy-on]

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Cation

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A positively charged ion that is formed when a neutral atom, typically a metal, loses one or more electrons.

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Example: A neutral sodium atom (left) loses its single outer electron, resulting in a sodium cation (Na+) with a positive charge because it has more protons than electrons.

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Anion Noun

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[an-ahy-on]

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Anion

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A negatively charged ion that is formed when a neutral atom, typically a non-metal, gains one or more electrons.

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Example: A neutral chlorine atom gains an electron, resulting in more electrons than protons and creating a negatively charged ion (anion).

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Electrostatic Attraction Noun

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[ih-lek-troh-stat-ik uh-trak-shuhn]

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Electrostatic Attraction

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The force of attraction between oppositely charged particles, which is the fundamental force that holds ionic bonds together.

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Example: A positively charged sodium ion (Na+) and a negatively charged chloride ion (Cl-) pull toward each other due to an electrostatic force, forming an ionic bond.

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Molecule Noun

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[mol-i-kyool]

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Molecule

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An electrically neutral group of two or more atoms held together by covalent chemical bonds, forming a distinct unit.

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Example: This image shows that a molecule, like water (H₂O), is formed when individual atoms (two hydrogen and one oxygen) join together.