Unit 5 Nomenclature 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 Al 3+ is aluminum ion For anions: Second word Change the ending of the elemental name to -ide Examples: Cl is chlorine Cl – is chloride ion S is sulfur S 2– is sulfide ion

Binary Ionic Nomenclature Metal (Group 1 or 2) + Nonmetal Name Cation first, then anion Examples: CaCl 2 : Calcium chloride MgO: Magnesium oxide

Practice: Name the Compounds NaCl A) Sodium Chlorine B) Chloride Sodium C) Sodiuide Chlorine D) Sodium Chloride MgI 2 A) Magnesium Iodine B) Magneside Iodide C) Magnesium Iodide D) Iodide Magnesium

Practice: Name the Compounds BaI 2 Barium Iodide CaBr 2 Calcium Bromide

Now Reverse it: Given the name, write the chemical formula EX: Aluminum Chloride  AlCl 3 Steps: 1)Identify the element symbols Al Cl 2) Write the charge on top for what the ions will be Al 3+ Cl - 3) Use criss-cross method to identify the subscript numbers Al 3+ Cl - AlCl 3

Practice: Write the Chemical Formulas Calcium Iodide Ca I Ca 2+ I - (Criss-cross) CaI 2 Sodium Nitride Na N Na + N 3- (Criss-cross) Na 3 N

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 NH 4 1+ Sulfate SO 4 2-

Polyatomic Ions DO NOT change the subscripts of atoms within the ion Phosphate ion: PO 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: (PO 4 3- ) 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: (NH 4 )Cl: Ammonium chloride If polyatomic is the anion, then name the cation and list the polyatomic name Ex: Mg (NO 3 ) 2 Magnesium nitrate

Practice Name this compound: NaNO 3 A.Sodium nitrate B.Sodium nitrite C.Sodium nitrogen oxide Name this compound: Na 2 SO 4 Sodium Sulfate

Given the Name of a Polyatomic Ion, find the Chemical Formula Follow the same criss-cross rules EX: Ammonium Oxide 1.Identify the symbols (NH 4 ) and O 2.Identify the charges on the ions NH 4 + O 2- 3.Criss-Cross charges to become the subscripts (NH 4 ) 2 O 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? A.Ca 2 (PO 4 ) 3 B.Ca 3 (PO 4 ) 2 1.Calcium is Ca and Phosphate is PO 4 2.Ca ion will have a 2+ charge and Phosphate ion will have a 3- charge 3.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. Use the Stock system only whenever more than one ion charge is possible for an element. Exceptions Roman numerals are: Not needed Needed Ag + Transition metals Cd 2+ Sn, Pb Zn 2+

Stock System Nomenclature Name to chemical formula Criss cross the charges Iron (II) nitride Fe 2+ N 3- Fe 3 N 2

Write the chemical formulas for the following compounds: ***Remember to cross the charges! 1. Tin (II) fluoride 2.Mercury (II) iodide 3.Lead (IV) sulfate 4.Cadmium oxide SnF 2 HgI 2 Pb(SO 4 ) 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 O 2- 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!!! 1.HgS 2.CoF 3 3.PbCl 2 4.ZnBr 2 5.Fe 2 O 3 Mercury (II) oxide Cobalt (III) fluoride Lead (II) chloride Zinc bromide Iron (III) oxide