Ionic Bonding

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Valence Electron Noun

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[vay-lence i-lek-tron]

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Valence Electron

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An electron in an atom's outermost shell that is responsible for its chemical properties and ability to form bonds.

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Example: This diagram of a Sodium atom shows its electrons in shells; the single electron in the outermost shell is the valence electron.

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Ion Noun

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[ahy-on]

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Ion

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A charged particle formed when a neutral atom or molecule gains or loses one or more of its valence electrons.

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Example: A neutral sodium atom, with an equal number of protons and electrons, loses one electron to become a positively charged sodium ion (Na+).

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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 an atom, typically a metal, loses one or more valence electrons.

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Example: A neutral sodium atom (Na) loses its outer electron, forming a positively charged sodium ion (Na+), which is called a cation.

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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 an atom, typically a nonmetal, gains one or more valence electrons.

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Example: A neutral chlorine atom gains an electron, filling its outer shell and becoming a negatively charged chloride ion (anion).

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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 through the strong electrostatic attraction that exists between two oppositely charged ions.

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Example: A sodium atom transfers one electron to a chlorine atom, creating a positive sodium ion (Na+) and a negative chloride ion (Cl-) 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 type of chemical bond that is formed when two atoms achieve stability by sharing one or more valence electrons.

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Example: A central oxygen atom shares its outer electrons with two hydrogen atoms, forming strong covalent bonds to create a single water molecule (H₂O).

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Metallic Bond Noun

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[muh-tal-ik bond]

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Metallic Bond

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A chemical bond where valence electrons are delocalized and shared among many metal atoms, forming a 'sea' of electrons.

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Example: This diagram shows that in a metal, positive metal ions are held together in a fixed structure by a 'sea' of shared, free-moving electrons.

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Octet Rule Noun

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[ok-tet rool]

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Octet Rule

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A chemical rule stating that atoms tend to gain, lose, or share electrons to achieve a full outer shell.

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Example: This diagram of an oxygen atom shows it has six outer shell electrons, so it needs two more to achieve a stable octet.

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Electronegativity Noun

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[i-lek-troh-neg-uh-tiv-i-tee]

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Electronegativity

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A measure of the tendency of an atom to attract a bonding pair of electrons towards itself in a chemical bond.

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Example: The more electronegative oxygen atom pulls electrons away from the hydrogen atoms, creating a partial negative charge on the oxygen and partial positive charges on the hydrogens.

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Lewis Dot Structure Noun

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[loo-is dot struk-cher]

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Lewis Dot Structure

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A diagram that visually represents an atom's valence electrons as dots placed around the chemical symbol of the element.

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Example: This Lewis dot structure shows a central carbon atom sharing electrons with four chlorine atoms, forming covalent bonds to complete their outer electron shells.