Naming Ionic and Covalent Compounds

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Ionic Compound Noun

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[eye-on-ik kom-pound]

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Ionic Compound

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A chemical compound composed of a metal and a non-metal, formed by the complete transfer of electrons between atoms.

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Example: A sodium atom transfers an electron to a chlorine atom, creating a positive sodium ion and a negative chloride ion, which then form an ionic compound.

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Covalent Compound Noun

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[co-vay-lent kom-pound]

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Covalent Compound

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A chemical compound typically composed of two non-metals, formed by the sharing of electrons between the constituent atoms.

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Example: This image shows a model of a carbon dioxide (CO₂) molecule, a common covalent compound where carbon and oxygen atoms are joined by sharing electrons.

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Ion Noun

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[eye-on]

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Ion

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An atom or molecule that has a net electrical charge due to the loss or gain of one or more electrons.

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Example: A neutral sodium atom (Na) with equal protons and electrons becomes a positively charged sodium ion (Na+) when it loses an electron.

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Cation Noun

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[kat-eye-on]

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Cation

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A positively charged ion, which is typically a metal atom that has lost one or more of its valence electrons.

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Example: A neutral sodium (Na) atom loses its outer electron, resulting in more protons than electrons and forming a positively charged ion called a cation (Na+).

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Anion Noun

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[an-eye-on]

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Anion

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A negatively charged ion, which is typically a non-metal atom that has gained 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 anion (Cl⁻).

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Ionic Bond Noun

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[eye-on-ik bond]

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Ionic Bond

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A chemical bond formed through the electrostatic attraction between two oppositely charged ions, a cation and an anion.

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Example: A sodium atom gives an electron to a chlorine atom. This creates oppositely charged ions (Na+ and Cl-) that attract, forming an ionic bond.

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Oxidation Number Noun

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[ok-si-day-shun num-ber]

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Oxidation Number

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The charge on a simple ion, representing the number of electrons an atom has gained or lost to form that ion.

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Example: This table shows that a single element, manganese (Mn), can have different oxidation numbers (like +2, +4, or +7) in different chemical compounds.

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Polyatomic Ion Noun

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[pol-ee-uh-tom-ik eye-on]

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Polyatomic Ion

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A group of covalently-bonded atoms that acts as a single unit and possesses an overall net electrical charge.

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Example: This image shows examples of polyatomic ions (groups of atoms with a charge) and compares them to monatomic ions (single atoms with a charge).

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Transition Metal Noun

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[tran-zish-un met-ul]

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Transition Metal

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A metal that can have more than one possible positive charge as an ion, requiring a Roman numeral in its name.

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Example: Transition metals, like iron and copper, can form ions with different charges, so their names in ionic compounds include a Roman numeral to show the charge.

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Formula Unit Noun

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[for-myoo-luh yoo-nit]

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Formula Unit

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The simplest whole-number ratio of cations and anions that represents the empirical formula of an ionic compound.

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Example: This image shows one sodium ion (Na+) and one chloride ion (Cl-), which represent the 1:1 ratio that makes up the formula unit for the ionic compound NaCl.