Ch. 7-1 Naming Compounds Names & Formulas

POINT > Name and identify the charge of monatomic ions POINT > Define and determine formulas for binary compounds POINT > Define and name polyatomic ions

POINT > Name and identify the charge of monatomic ions Metals in Groups 1A, 2A, 3A lose electrons forming (+) charged cations The atoms lose the number of electrons needed to fulfill the octet rule (Noble gas config) The cation name is the same as the atom, followed by ion or cation (ex. Na+ = sodium ion)

WB CHECK: Write the symbol and name of the ion formed by: Lithium  Li+ lithium ion Calcium  Aluminum  Potassium 

POINT > Name and identify the charge of monatomic ions Nonmetals gain electrons forming (-) charged anions The ions gain the number of electrons needed to fulfill the octet rule (Noble gas config) The name of the anion is the stem of the element name, ending in -ide (ex. O2- = oxide ion)

WB CHECK: Write the symbol and name of the ion formed by: Chlorine  Cl- chloride ion Phosphorus  Sulfur  Nitrogen 

POINT > Name and identify the charge of monatomic ions Many transition metals can form more than one cation, each having a different ionic charge Ex. Iron cation could be Fe2+ or Fe3+ Charge must be determined based on the name or formula of a compound (can’t just use group numbers…)

POINT > Name and identify the charge of monatomic ions Stock system for naming transition metal cations: Roman numerals after the name indicate the charge Ex. Iron: Fe2+ written as iron(II) ion Fe3+ written as iron (III) ion

POINT > Name and identify the charge of monatomic ions Classical system for naming transition metal cations: Latin (or other) root/suffix indicates the charge: -ic refers to higher charge, -ous refers to lesser charge Ex. Iron: Fe2+ written as ferrous ion Fe3+ written as ferric ion

POINT > Define and determine formulas for binary compounds Binary compounds are composed of two elements Ex. H2O HCl CO2 NaCl NH3 If the compound is ionic, the cation is written first and the charges of the ions must be balanced

POINT > Define and determine formulas for binary compounds Ex. Determine the name and formula of a compound of iodine and magnesium Iodide ion is I- and magnesium ion is Mg2+ Two I- are needed to balance with one Mg2+ So formula unit would be MgI2 = magnesium iodide

WB CHECK: Determine the formula and name of a compound of: oxygen and potassium iron(II) and chlorine sulfur and copper(I) strontium and nitrogen bromine and lithium

POINT > Define and determine formulas for binary compounds Because compounds are electrically neutral, you can determine the formula of an ionic compound this way: The charge on the cation becomes the subscript on the anion The charge on the anion becomes the subscript on the cation

POINT > Define and determine formulas for binary compounds If these subscripts are not in the lowest whole-number ratio, divide them by the greatest common factor

WB CHECK: What is the formula unit of: calcium flouride zirconium(I) carbide sodium sulfide aluminum oxide barium selenide

POINT > Define and determine formulas for binary compounds All of the examples you just encountered were ionic compounds The charges in an ionic compound must balance, so to name them and determine formulas is straightforward.. Atoms in a binary molecular compound can combine in different ways (ex. CO and CO2, H2O and H2O2)

POINT > Define and determine formulas for binary compounds Atoms in a binary molecular compound can combine in different ways (ex. CO and CO2, H2O and H2O2) To name binary molecular compounds use prefixes to show the number of each type of atom in the compound Ex. CO2 is carbon dioxide CO is carbon monoxide

POINT > Define and determine formulas for binary compounds Rules for naming binary molecular compounds: Confirm two nonmetals Name elements in the order of formula Use prefixes to indicate numbers “mono” can be left out if it’s the first element Ex. CO2 is carbon dioxide, not monocarbon dioxide

POINT > Define and determine formulas for binary compounds Rules for naming binary molecular compounds: Second element must end in –ide Ex. What is the name of N2Cl5? dinitrogen pentachloride

WB CHECK: Write the name of the molecular compound: CO SO3 SO2 N2S3 K3F2

POINT > Define and determine formulas for binary compounds To write the formula of a molecular compound, use the prefixes to identify the subscript of each element Ex. Hexasulfur tetrachloride would be… S6Cl4 Remember: Molecular formulas do not get reduced, because they indicate the actual number of atoms present in an actual molecule

Write the formula of the molecular compound: Phosphorus trichloride WB CHECK: Write the formula of the molecular compound: Phosphorus trichloride Dinitrogen tetroxide Triselenium hexafluoride Dihydrogen monoxide

POINT > Define and name polyatomic ions Polyatomic ions are groups of atoms covalently bonded together that, as a whole, have a charge Ex. NO3- SO32- PO43- OH- NH4+ These form ionic bonds with other ions: Ex. NaNO3 MgSO3 Li3PO4 KOH NH4Cl Charges must balance, just as with ionic compounds

POINT > Define and name polyatomic ions Most polyatomic ions are negatively charged and most contain oxygen Ex. NO3- SO32- PO43- OH- NH4+ These form ionic bonds with other ions: Ex. NaNO3 MgSO3 Mg3(PO4)2 Mg(OH)2 NH4Cl

POINT > Define and name polyatomic ions Most polyatomic anions end in -ite or -ate -ite indicates fewer oxygen present -ate indicates more oxygen present Ex. SO32- = sulfite ion SO42- = sulfate ion ClO2- = chlorite ion ClO3- = chlorate ion

POINT > Define and name polyatomic ions Sometimes there are more than two possible numbers of oxygen in a “family” hypo- is added as prefix when fewer oxygen are present (-ite remains as suffix) ClO- Hypochlorite

POINT > Define and name polyatomic ions Sometimes there are more than two possible numbers of oxygen in a “family” per- is added as prefix when more oxygen are present (-ate remains as suffix) ClO4- Perchlorate

POINT > Define and name polyatomic ions Note: Adding/removing oxygen does not change the charge of the polyatomic ion Sometimes a hydrogen is a part of the polyatomic ion. If so, the name includes hydrogen and the charge is reduced by 1 Ex. sulfate = SO42- hydrogen sulfate = HSO4-

WB CHECK: PO53- PO42- PO33- PO32- If a phosphate ion, PO43- has a charge of 3- then the formula and charge of a phosphite ion would be PO53- PO42- PO33- PO32-

intermolecular forces hydrogen bonding WB CHECK: The atoms within a polyatomic ion are held together by ionic bonds covalent bonds intermolecular forces hydrogen bonding

WB CHECK: If nitrate is NO3- what is nitrite? If sulfite is SO32- what is sulfate?

WB CHECK: What is the formula of potassium sulfate? What is the formula of magnesium nitrite? What is the name of Na3PO4? What is the name of (NH4)2SO3?

Homework: Read pages 207-219 Practice #1-2 page 211 Practice #1-2 page 213 Practice #1-2 page 215 Practice #1-2 page 217 F.A. #1-5 page 219