REVIEW. Naming Ionic, Covalent and Multivalent Molecules NEW REVIEW.... Naming Ionic, Covalent and Multivalent Molecules NEW.... Polyatomic Ions

Step 1: Ionic or Covalent? Metal + Non-Metal atoms “Give & Take” electrons Covalent Non-Metal atoms ONLY! “Share” electrons Step 1 is to Ask...... Is there a metal? Yes = Ionic No = Covalent

If it’s Ionic: (and there are only 2 elements) Ask: Does the metal form only 1 kind of ion or more than one? Only 1 = simple ionic naming More than one = multivalent ionic naming

Simple Ionic Naming Like MgO Name the metal (the positive ion): magnesium. Write the root of the non-metal (the negative ion): oxygen. Add -ide to the end of the non-metal to form: magnesium oxide. Name: LiF MgI2 Fe2O3 Lithium fluoride Magnesium Iodide Iron(III)Oxide

Multivalent Ionic Naming Like MnO2 Write the usual ionic name manganese oxide Decide which metal ion was used: Write the ion charge of the non-metal Count the number of each atom Calculate the negative charge Determine what the charge needs to be on the metal ion to balance out the non-metal Add the number of the ion charge in Roman Numerals in brackets after the metal manganese(IV) oxide Mn O 2- Number of atoms 1 2 Charge (1 Mn atom) x ( ? charge) = +4 (2 atoms) x (2- charge) = -4 charge +4

Name Fe2O3 Fe O 2- Write the usual ionic name iron oxide Decide which metal ion was used: Write the ion charge of the non-metal Count the number of each atom Calculate the negative charge Determine what the charge needs to be on the metal ion to balance out the non-metal Add the number of the ion charge in Roman Numerals in brackets after the metal iron(III) oxide Fe O 2- Number of atoms 2 3 Charge (2 atoms) x ( ? charge) = + 6 (3 atoms) x (2- charge) = -6 charge

If it’s covalent: 1. Does it start with H or have more than 2 atoms in the molecule? Yes = Look up the name example: H2O = water No = Name the ‘binary’ covalent molecule with the prefix system N2O4 = dinitrogen tetraoxide (made up of only 2 non-metals)

Naming a binary covalent molecule: Like Si3P6 Write the most metallic atom (farthest left) first Silicon Add -ide to the root of the second atom’s name phosphide Add a prefix before each atom’s name to indicate the number of atoms in the molecule. (Do not add a prefix to the first atom if there is only 1) Name: PF5 P4O10 N2O Phosphorus Tetraphosphorous Dinitrogen pentafluoride decaoxide monoxide Trisilicon hexaphosphide

What if it’s an ionic bond (metal + non-metal) but there are more than 2 elements? These are called ‘polyatomic’ ions many atoms

Polyatomic Ions Polyatomic ions are 2 or more atoms joined together with covalent bonds but together they act as a single ion... Like a posse Wherever 1 member of the posse goes... The whole group goes Whatever mood one member of the posse is in (positive or negative) the whole group is in the same mood The posse is always protected... The members must always stick together!

Polyatomic Ions Examples: OH- : a posse... Not just O and not just H, but always OH together! NO2- : the negative belongs to the N and the O’s together Are all posse’s negative? What about the “Leadership Group” at Boucherie??? They give candy! They are a ‘positive’ posse! NH4+: the ENTIRE group is positive The negative mood is felt by the ENTIRE posse, not just the H or the O

Polyatomic Ions See pages 192 - 193 Polyatomic ions are 2 or more atoms joined together with covalent bonds but together they act as a single ion... The whole group has a + or – charge, not the individual atoms. What is the name of the compound KClO? K+ = potassium ClO– = hypochlorite potassium hypochlorite

Polyatomic Compounds Polyatomic ions will act as a non-metal if they are negative or a metal if they are positive (and giving like mothers)

Polyatomic Compounds Examples: Na+ and OH- = it takes the entire OH posse to get together and take the electron away from Na NaOH = Sodium hydroxide Mg(OH)2 = protect the posse! Put brackets around it! Mg is a bit of a tough guy (2+ ion) so it takes two OH posses to get together and steal its electrons Ca(NO2) 2 Two polyatomic ions together: NH4OH

Naming Polyatomic Compounds This is an easy one! Write the name of the metal or the name of the positive polyatomic ion (ammonium is the only one – NH4) Write the name of the negative polyatomic ion MgCr2O7 = magnesium dichromate

Let’s make a naming poster... Is there a metal? Yes = Ionic Simple Ionic Naming Multivalent Compound Naming Polyatomic Compound Naming No = Covalent Start with H or more than 2 atoms Binary Covalent Compound Naming Rules for Naming Continue with the rules for naming each branch and give an example for each... If you finish early... Work on the review assignment – Due Monday