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Unit 5 Nomenclature. Naming Substances. Chemical Nomenclature. Chemical nomenclature : the organized system used to name substances and write their chemical formulas .
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Unit 5Nomenclature Naming Substances
Chemical Nomenclature • Chemical nomenclature: the organized system used to name substances and write their chemical formulas. • Chemical formula: uses element symbols and subscript numbers to represent the number of each kind of atom bonded together in a substance • Subscript: indicates the number of atoms or ions present in the formula
Example of a Chemical Formula Formula for water
Naming Ionic Compounds Part 1
Review: What is an Ion? • A charged atom due to the gain or loss of electrons • Cation: Positively charged ion due to the loss of electrons • Anion: Negatively charged ion due to the gain of electrons
Ionic Compounds • Ionic compounds are formed when oppositely charged ions are attracted to each other. • Strong electrostatic attractions. • High melting point and boiling point solids. • Capable of dissolving in water. • Formed between a metal and a nonmetal
Monatomic Ionic Nomenclature For cations: • First word • Keeps its elemental name • Examples: Na+is sodium ion Al3+ is aluminum ion For anions: • Second word • Change the ending of the elemental name to -ide • Examples: Cl is chlorineCl– is chloride ionS is sulfurS2– is sulfide ion
Binary Ionic Nomenclature Metal (Group 1 or 2) + Nonmetal Name Cation first, then anion Examples: • CaCl2 : Calcium chloride • MgO: Magnesium oxide
Practice: Name the Compounds NaCl A) Sodium ChlorineB) Chloride SodiumC) Sodiuide ChlorineD) Sodium Chloride MgI2 A) Magnesium IodineB) Magneside IodideC) Magnesium IodideD) Iodide Magnesium
Practice: Name the Compounds • BaI2 Barium Iodide • CaBr2 Calcium Bromide
Now Reverse it: Given the name, write the chemical formula • EX: Aluminum Chloride AlCl3 • Steps: • Identify the element symbols Al Cl 2) Write the charge on top for what the ions will beAl3+ Cl- 3) Use criss-cross method to identify the subscript numbers Al3+ Cl- AlCl3
Practice: Write the Chemical Formulas • Calcium Iodide Ca I Ca2+ I- (Criss-cross) CaI2 • Sodium Nitride Na N Na+ N3- (Criss-cross) Na3N
Polyatomic Ions • Polyatomic ions are ions made up of more than one atom that act as an individual ion in a compound • The charge applies to the entire group of atoms • Examples: • Ammonium NH41+ • Sulfate SO42-
Polyatomic Ions • DO NOT change the subscripts of atoms within the ion • Phosphate ion: PO43- • 4 means there are 4 Oxygen atoms in the ion • 3- means the entire ion has a charge of negative 3
Polyatomic Ions • If more than one polyatomic ion is needed, put parentheses around the ion, then add the subscript after the parentheses • Ex: (PO43-)2 indicates there are two phosphate ions
Naming Polyatomic Ions when Given a Chemical Formula • If polyatomic is the cation, then list the name & add the anion name to the end • Ex: (NH4)Cl: Ammonium chloride • If polyatomic is the anion, then name the cation and list the polyatomic name • Ex: Mg (NO3)2Magnesium nitrate
Practice Name this compound: NaNO3 • Sodium nitrate • Sodium nitrite • Sodium nitrogen oxide • Name this compound: Na2SO4 Sodium Sulfate
Given the Name of a Polyatomic Ion, find the Chemical Formula • Follow the same criss-cross rules • EX: Ammonium Oxide • Identify the symbols(NH4) and O • Identify the charges on the ionsNH4+ O2- • Criss-Cross charges to become the subscripts(NH4)2O Remember: If you need multiples of the polyatomic ion, put the formula in parentheses and add a subscript after the parentheses
Practice: Name to Chemical Formula • What is the formula for Calcium Phosphate? • Ca2(PO4)3 • Ca3(PO4)2 Calcium is Ca and Phosphate is PO4 Ca ion will have a 2+ charge and Phosphate ion will have a 3- charge Criss-cross: the 3 becomes the subscript for Ca, the 2 becomes the subscript for the Phosphate group
Stock System- Ionic Compounds • Transition Metal and Nonmetal • Many Transition Metals have more than one charge • Roman Numerals are used to indicate the charge • Manganese (VII) Oxide (manganese has a +7 charge) • Lead (IV) Oxide (lead has a +4 charge)
Stock System- Ionic Compounds • Use the Stock system only whenever more than one ion charge is possible for an element. • Exceptions Roman numerals are: Not neededNeeded Ag+ Transition metals Cd2+Sn, Pb Zn2+
Stock System Nomenclature • Name to chemical formula • Criss cross the charges • Iron (II) nitride Fe2+ N3- Fe3N2
Write the chemical formulas for the following compounds:***Remember to cross the charges! • Tin (II) fluoride • Mercury (II) iodide • Lead (IV) sulfate • Cadmium oxide • SnF2 • HgI2 • Pb(SO4)2 • CdO
Stock System Nomenclature • Chemical formula to name • Split the compound • Find the charge of the anion side • Cation side + anion side = 0 • CuO Cu O2- Cu must have a +2 charge for the charges to add to 0 Copper (II) oxide
Name the following compounds:**Remember the overall charge of a compound is 0!!! • HgS • CoF3 • PbCl2 • ZnBr2 • Fe2O3 • Mercury (II) oxide • Cobalt (III) fluoride • Lead (II) chloride • Zinc bromide • Iron (III) oxide