NAMING COMPOUNDS

• Ions


  Particles with an overall electric charge
• Categories of ions


  • Positive (cations)
  • Negative (anions)
• Cations


  • Charges can be 1+, 2+, 3+, or 4+
• Anions


  • Charges can be 1-, 2-, or 3-
• Monatomic ion


  Composed of a single atom
• Polyatomic ion


  Particle with two or more covalently bonded atoms and an overall electric charge
• Hydrogen ions


  H+ (protons) in acids, H- (hydride) when bonded to metals
• Metal ions


  • More than 70% of naturally occurring elements are metals
  • Neutral metal atoms tend to lose electrons to form positive ions
  • In ionic compounds, metal atoms are nearly always monatomic cations
  • Charge can be 1+, 2+, 3+, or 4+
• Metals that form only one ion


  • Metals in columns 1 and 2
  • Ni2+
  • Ag+
  • Zn2+
  • Cd2+
  • Al3+
• Naming metal ions that form only one ion

  Ion name is the element name
• Naming metal ions that form more than one ion

  Systematic name is element name followed by roman numeral in parentheses showing positive charge
• 10 metal ions to memorize

  • Cu+
  • Cu2+
  • Fe2+
  • Fe3+
  • Sn2+
  • Sn4+
  • Hg22+
  • Hg2+
  • Pb2+
  • Pb4+
• Do not use roman numerals in systematic names for metal ions that can form only one stable ion
• Monatomic anions


  • Fluoride
  • Chloride
  • Bromide
  • Iodide
  • Oxide
  • Sulfide
  • Nitride
  • Phosphide
• Naming monatomic anions


  Root of element name followed by -ide
• Polyatomic ions with negative charges that contain oxygen are called oxoanions
• Hydroxide ion


  Particle with 8 protons and 10 electrons, overall negative charge attached to oxygen
• Polyatomic ions will be considered in more detail when studying the three-dimensional structure of particles

  
• At this point, our interest is the ratios in which ions combine
• Monatomic ion


  Charge with one atom attached
• Polyatomic ion


  Charge with several atoms attached
• The charges on the ions determine the ratios of the ions in compounds
• The number of atoms in an ion is a factor in writing the formula for the compound, but it does not affect the ratio of the ions in the compound
• Polyatomic cations to memorize

  • NH4+ (ammonium)
  • H3O+ (hydronium)
  • Hg22+ (mercury (I) or mercurous)

  
• Oxoanions


  Polyatomic ions with negative charges that contain oxygen
• Oxoanion naming system


  • Per-root-ate ion has X oxygen atoms
  • Root-ate ion has the same charge and one fewer oxygens
  • Root-ite ion has the same charge and 2 fewer oxygens
  • Hypo-root-ite ion has the same charge and 3 fewer oxygens
• When there are two oxyanions, the ion named root-ite has the same charge and one less oxygen than the root-ate
• Ionic compounds must have both positive and negative ions
• The overall charge of any combination of ions must be zero
• Ionic compound composition


  • Name
  • Solid formula
  • Balanced, separated ions
• For ionic compounds, the key is to first write the separated-ions formula that shows the number and formulas of the ions, including their charges
• Writing solid formulas from names

  1. Write the balanced separated-ions first

  2. Balance the charges
• Binary compounds


  • NaCl
  • Na2S
  • MgBr2
  • HCl
  • AlN
• Acids


  • H2SO4
  • H2CO3
  • H5IO6
  • HBr
  • CH3COOH
• Compounds of two nonmetals

  • PCl3
  • SO3
  • CO
  • As2F6
  • CCl4