polyatomic ion

(noun)

A charged species composed of two or more atoms covalently bonded, or of a metal complex that acts as a single unit in acid-base chemistry or in the formation of salts. Also known as a molecular ion.

Related Terms

  • monatomic ion
  • electrically neutral
  • noble gas
  • empirical formula
  • anion
  • cation

(noun)

An ion composed of several atoms.

Related Terms

  • monatomic ion
  • electrically neutral
  • noble gas
  • empirical formula
  • anion
  • cation

(noun)

A charged species (ion) composed of two or more atoms covalently bonded. Also known as a molecular ion.

Related Terms

  • monatomic ion
  • electrically neutral
  • noble gas
  • empirical formula
  • anion
  • cation

(noun)

A set of covalently bonded atoms that have an overall charge, making them an ion.

Related Terms

  • monatomic ion
  • electrically neutral
  • noble gas
  • empirical formula
  • anion
  • cation

Examples of polyatomic ion in the following topics:

  • Lewis Structures for Polyatomic Ions

    • Lewis structures for polyatomic ions are drawn by the same methods that we have already learned.
    • When counting electrons, negative ions should have extra electrons placed in their Lewis structures; positive ions should have fewer electrons than an uncharged molecule.
    • Negative ions follow the same procedure.
    • The chlorite ion, ClO2–, contains 19 (7 from the Cl and 6 from each of the two O atoms) +1 = 20 electrons.
    • The hypochlorite ion, ClO−, contains 13 + 1 = 14 electrons.
  • Formulas of Ionic Compounds

    • Polyatomic ions are a set of covalently bonded atoms that have an overall charge, making them an ion.
    • For example, the hydroxide ion has the formula OH-1.
    • When creating ionic compounds with these polyatomic ions, treat them the same way as typical monatomic ions (only one atom).
    • The parentheses were used to indicate that OH was a polyatomic ion and came as a "package deal."
    • Parentheses are always used when the compound contains multiples of the polyatomic ion.
  • Naming Acids and Bases

    • Any polyatomic ion with the suffix "-ate" uses the suffix "-ic" as an acid.
    • When you have a polyatomic ion with one more oxygen than the "-ate" ion, then your acid will have the prefix "per-" and the suffix "-ic."
    • For example, the chlorate ion is ClO3-.
    • With one fewer oxygen than the "-ate" ion, the acid will have the suffix "-ous."
    • Most strong bases contain hydroxide, a polyatomic ion.
  • Ions

    • An ion consisting of a single atom is a monoatomic ion; an ion consisting of two or more atoms is referred to as a polyatomic ion.
    • Ions are highly reactive species.
    • These representations can be thought of as equivalent for monoatomic ions, but the Roman numerals cannot be applied to polyatomic ions.
    • Polyatomic and molecular ions can also be formed, generally by gaining or losing elemental ions, such as H+, in neutral molecules.
    • Polyatomic ions are generally very unstable and reactive.
  • Naming Ionic Compounds

    • Usually, the positively charged portion consists of metal cations and the negatively charged portion is an anion or polyatomic ion.
    • But to be considered an ion, they must carry a positive or negative charge.
    • If either the cation or the anion was a polyatomic ion, the polyatomic ion name is used in the name of the overall compound.
    • The polyatomic ion name stays the same.
    • Since the net charge of the ionic compound must be zero, the Cu ion has a 2+ charge.
  • Formulas of Ionic Compounds

    • Ionic formulas must satisfy the noble gas configurations for the constituent ions and the product compound must be electrically neutral.
    • If the anion is a polyatomic ion, its suffix can vary, but is typically either -ate or -ite,as in the cases of sodium phosphate and calcium nitrite, depending on the identity of the ion.
    • A lesson on writing formulas for binary ionic compounds as well as ionic compounds containing polyatomic ions.
  • Electron Configuration of Cations and Anions

    • These charged atoms are known as ions.
    • Ionization is not limited to individual atoms; polyatomic ions can also be formed.
    • Polyatomic and molecular ions are often created by the addition or removal of elemental ions such as H+ in neutral molecules.
    • The two notations are therefore exchangeable for monatomic ions, but the Roman numerals cannot be applied to polyatomic ions.
    • However, it is possible to mix the notations for the individual metal center with a polyatomic complex, as demonstrated using the uranyl ion (UO2) as an example.
  • Salts that Produce Basic Solutions

    • As such, salts are composed of cations (positively charged ions) and anions (negative ions), and in their unsolvated, solid forms, they are electrically neutral (without a net charge).
    • The component ions in a salt can be inorganic; examples include chloride (Cl−), the organic acetate (CH3COO−), and monatomic fluoride (F−), as well as polyatomic ions such as sulfate (SO42−).
    • The bicarbonate ion is the conjugate base of carbonic acid, a weak acid.
    • But because HCl is a strong acid, the Cl- ion is not basic in solution, and it isn't capable of deprotonating water.
    • Because the bicarbonate ion is the conjugate base of carbonic acid, a weak acid, sodium bicarbonate will yield a basic solution in water.
  • Naming Coordination Compounds

    • The procedure for naming ionic compounds containing polyatomic ions is the same as that for naming simple ions.
    • Thus, CaCO3 is named calcium carbonate; (NH4)2HPO4, a compound with two polyatomic ions, is named ammonium hydrogen phosphate; and Pb2+ paired with SO42- (PbSO4) is named lead(II) sulfate.
    • When naming a complex ion, the ligands are named before the metal ion.
    • Write the name of the central atom/ion.
    • Tetrachloridonickelate(II) ion.
  • Polyatomic Molecules

    • A polyatomic molecule is a single entity composed of at least three covalently-bonded atoms.
    • Polyatomic molecules are electrically neutral groups of three or more atoms held together by covalent bonds.
    • Molecules are distinguished from ions by their lack of electrical charge.
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