Formulas & Nomenclature Chapter 4 WHS Chemistry

Na Cl Do you know what sodium chloride is? Do you know what symbols are involved in expressing sodium chloride? Na Cl

MgS CaO LiBr Magnesium sulfide Calcium oxide Lithium bromide Try identifying what elements and symbols are involved in the compounds. MgS Magnesium sulfide CaO Calcium oxide LiBr Lithium bromide What does each begin with? Where is it on PT? What does each end with? What suffix does each name use? Where is it on PT?

Start with simple naming—pay attention to where these elements are on the periodic table! The cation is almost always listed first in the formula & named first. The cation is named using the element name. The anion is almost always listed last in the formula & named last using –ide ending.

Let’s try some (ignore the little subscripts for now) Compound name CsF AlCl3 MgI2 Rb2O SrI2 K2S cesium fluoride aluminum chloride magnesium iodide rubidium oxide strontium iodide potassium sulfide

To put the formulas together correctly, we need to know some basics about the typical charges of the elements. It is also important to remember that as we put these together, we must charge balance! Try a few on your paper.

Notice that some metals have several charges possible. …look on your periodic table, where are most of these located? Try putting some of these with Cl- Fe2+ Fe3+ Ni2+ Ni3+ Cu+ Cu2+ Sn2+ Sn4+ Hg22+ Hg2+ Pb2+ Pb4+

copper ( ) chloride mercury ( ) oxide iron ( ) oxide Compound Decide which charge is used name CuCl HgO Fe2O3 MnO2 PbCl4 Ni2S3 copper ( ) chloride mercury ( ) oxide iron ( ) oxide manganese ( ) oxide lead ( ) chloride nickel ( ) sulfide

What do the Roman numerals tell us? iron (III) sulfide lead (II) nitride

calcium bromide magnesium oxide silver nitride tin ( ) chloride Compound Do we need a Roman numeral? name CaBr2 MgO Ag3N SnCl2 CuF2 K3P Zn3N2 HgO calcium bromide magnesium oxide silver nitride tin ( ) chloride copper ( ) fluoride potassium phosphide zinc nitride mercury ( ) oxide

NO3- SO42- Polyatomic Ions What is different about these? What type of bond is likely holding these together? How might they act if a Mg2+ ion came along?

barium nitrite iron ( ) hydroxide potassium nitrate sodium sulfate Compound Show the polyatomic ion name Ba(NO2)2 Al2(CO3)3 Fe(OH)3 KNO3 (NH4)3PO4 (NH4)2SO4 Na2SO4 K3PO4 barium nitrite aluminum carbonate iron ( ) hydroxide potassium nitrate ammonium phosphate ammonium sulfate sodium sulfate potassium phosphate

NO2- Ca2+ K+ SO4-2 Cu2+ OH- Fe2+ CO3-2 Co3+ NO3- Ag+ NO3- NH4+ C2O4-2 Cation Poly-atomic ion Formula # atoms # ions Name calcium nitrite potassium sulfate copper (II) hydroxide iron (II) carbonate cobalt (III) nitrate silver nitrate ammonium oxalate tin (IV) phosphate Ca2+ NO2- K+ SO4-2 Cu2+ OH- Fe2+ CO3-2 Co3+ NO3- Ag+ NO3- NH4+ C2O4-2 Sn4+ PO4-3

Naming Acids For right now, we’ll define an acid as a compound which will give H+ when dissolved in water.... ....so when we look at a compound, the H is often the cation we will see. There are specific rules for naming acids, depending on the form of the anion.

Rules for naming Acids Binary acids: If the anion does not have oxygen...use prefix “hydro-” and suffix “-ic” Ternary acids: When anion has oxygen it is called an oxyacid...no prefix (hydro) is used, “-ate” polyatomic ion suffix goes to “-ic” “-ite” polyatomic suffix goes to “-ous” Acid Name HF HCl HBr HI HCN H2S hydrofluoric acid hydrochloric acid hydrobromic acid H3PO4 H2SO3 H2SO4 HNO2 HNO3 nitric acid hydroiodic acid nitrous acid hydrocyanic acid sulfuric acid hydrosulfuric acid sulfurous acid phosphoric acid

Name Ions formula potassium hydroxide sodium carbonate nitric acid cobalt (III) nitrate calcium chloride lead (IV) oxide dinitrogen pentoxide ammonium perchlorate K+ OH- KOH Na+ CO32- Na2CO3 -ic from nitrate H+ NO3- HNO3 Co3+ NO3- Co(NO3)3 Ca2+ Cl- CaCl2 Pb4+ O2- PbO2 don’t need N2O5 NH4+ ClO4- NH4ClO4