naming compounds names and formulas writing chemical formulas chemical formula: chemical formula: 1...

Naming Compounds

Names and Formulas

Writing Chemical Formulas

Chemical Formula:Chemical Formula: 1 – what elements 2 - ratios in compound

Metals(positive ions) written first Polyatomic Ions:Polyatomic Ions:

group of atoms that act as an element has its own ionic charge Always look on the Data Table for

name and ion charge

Ion Charge and the Formulas of Ionic

Compounds Law of Definite Proportions:Law of Definite Proportions:

a specific compound elements are always in definite proportions; integers no decimals or fractions

Ex: H2O – always 2 hydrogen atoms for one oxygen atom

Ionic compounds:Ionic compounds: metal + non-metal Electron(s) transferred bonded by electrical force (opp. charges

attract) electrically neutral


Compounds Ionic compounds:Ionic compounds:

metal + non-metal Positive ion + negative Cation + Anion

Formulas of Ionic Compounds

Use Cross-over Rule:


Compounds Formulas for Ionic Compounds with

Polyatomic Ions: Use crossover rule but

Polyatomic Ions --- MUST BE KEPT TOGETHER

Use brackets around polyatomic groups if there is more than 1


Compounds multivalent:multivalent:

element with more than 1 possible ion charge; occurs only after atomic # 20 – Ca Are in Transition metals on PT

Use crossover rule When naming the CHARGE is written in

roman numerals ex. Iron(III)(III)oxide

Naming Ionic Compounds

Rules for Naming Ionic Compounds: Metal(pos) ion written 1st name spelled same in lower case non-metal ion written 2nd given suffix “–ide”“–ide”

Naming Ionic Compounds

Naming Polyatomic Ions:Naming Polyatomic Ions: pos. polyatomic ions written 1st neg. polyatomic ions written 2nd; name of ion

not changed Use the data table

Do Exercise #4

Naming Ionic compounds using the formulaNaming Ionic compounds using the formula

Example 1: Example 1: AgAg22SOSO44 Silver is monovalent, so, no Roman Num. necessarySilver is monovalent, so, no Roman Num. necessary Look up SOLook up SO44 on table – sulphate on table – sulphate Therefore, name is Therefore, name is Silver sulphateSilver sulphate

Example 2: Example 2: CuCu22OO look at the total amt of charge on each half of formula:

The neg side O for oxygen is monovalent – has charge of 2- Therefore the pos side must have a charge of 2+ As there are 2 Cu, the charge on each Cu must be 1+

(1+ plus 1+ equals 2+) Therefore the name of the compound must be

Copper(I) oxide (remember multivalents must use Roman Numerals in the name)

Naming Ionic compounds using the Naming Ionic compounds using the formulaformula

Example 3: Example 3: FeSFeS Iron(Fe) is multivalent, so, Roman Num. necessaryIron(Fe) is multivalent, so, Roman Num. necessary Look up S on Periodic table – has a 2- chargeLook up S on Periodic table – has a 2- charge So, Fe must have a 2+ charge to balanceSo, Fe must have a 2+ charge to balance Therefore the name is Therefore the name is Iron(II) sulphideIron(II) sulphide

Example 4: Example 4: FeFe22(HPO(HPO44))33 look at the total amt of charge on each half of formula:

The neg side: eacg HPO4 has charge of 2- There are 3 HPO4 the neg side must have a charge of 6- (3 x 2- = 6-) As there are 2 Fe, the charge on each Fe must be 3+

(3+ plus 3+ equals 6+) Therefore the name of the compound must be

Iron(III) monohydrogen phosphate (remember multivalents must use Roman Numerals in the name)


Try It: 1 – Ag3PO4

2 – Al2(SO4)3

3 – Fe2S3

4 – CuCl 5 – (NH4)2CO3

6 – VCl3 7 – Hg2CO3

8 – CuSO4

9 – (NH4)2S

Answers: 1 – Silver phosphate 2 – Aluminum sulphate 3 – Iron(III) sulphide 4 – Copper(I) chloride 5 – Ammonium carbonate 6 – Vanadium(III) chloride 7 – Mercury(I) carbonate 8 – copper(II) sulphate 9 – Ammonium sulphide


Do Exercise #5 Do Handout: Writing formulas Quiz

(exercise in Names -> Formulas)

Do Handout: Formula Writing (exercise in Names -> Formulas)

Do Handout: Inorganic Nomenclature Test (may do as Test or Quiz)

Naming Ionic compounds using the formulaNaming Ionic compounds using the formulaHydratesHydrates

When a crystal of an ionic compound is grown by evaporation from aqueous solution, frequently it is found that the crystal structure will include water molecules

Molecules which include water molecules are called HYDRATES

Use prefixes to tell how many water molecules are attached;


Prefixes forPrefixes for HydratesHydrates 1 2 3 4 5 6 7 8 9 10

mono di tri

tetra penta hexa

hepta octa

nona deca


Prefixes forPrefixes for HydratesHydrates

Copper(II)sulphate pentahydrate

Zinc acetate dihydrate

Calcium nitrate tetrahydrate

Examples:

CuSO4*5H2O

Zn(CH3COO)2*2H2O

Ca(NO3)2*4H2O

Do exercise #6 & #7

Naming Covalent Compounds

Unlike Ionic compounds there are several various combinations of elements possible. Ionic example: sodium and chlorine always forms NaCl It is the ONLY possible combination This combination is called a formula unit; NOT

a molecule Covalent example: carbon and oxygen


Unlike Ionic compounds, Covalent compounds has numerous possibilities in how the elements can combine: Example: carbon and oxygen Can form CO or CO2 or CO3

Each has unique properties: CO will kill you while CO2 will not You cannot all these variations carbon oxide A different naming system is necessary


Prefix naming system – use prefixes to name the various covalent molecules

Note: these are molecules not formula units as with Ionic compounds

Examples of naming covalent molecules: carbon and oxygen can form CO or CO2 or CO3 CO is named carbon monoxide CO2 is named carbon dioxide CO3 has a special name carbonate – a polyatomic

structure


Prefixes indicates the number of the types of atoms in a molecule

monoditri

tetrapentahexa

heptaocta

nonadeca

12345678910


Rules for prefixes: 1 - don’t use mono for the first element if there is only one; 2 - always use mono for second element if there is only one atom in the molecule 3 - mono drops the 2nd “o” as in carbon monoxide 4 - second element ends with ‘ide’ 5 – add the appropriate prefix according to number of atoms present in molecule


The name of the molecule always reflects the structure of the molecule Example: P4O10 --- tetraphosphorus decaoxide

You can tell what the formula is by looking at the name;

or

You can tell what the name is by looking at the formula

This makes covalent compounds easy to name and easy to write the formula


REMEMBER: always determine to see if the compound is IONIC orCOVALENT Then follow the appropriate rules Do Exercise #8 & 9

Handout:Nomenclature

Flow Chart

Naming Acids

1 -- has NO oxygen name begins with ‘hydro’ ends with ‘ic’

examples: HF – hydrogen fluoride HCl – hydrogen chloride

2 types of acids:

hydrofluoric acid

hydrochloric acid

Naming Acids

examples: Formula Chemical Name: H2SO3 – hydrogen sulphite H2CO3 – hydrogen carbonate

sulphurous acid

carbonic acid

2 -- has oxygen There are 2 types of acids WITH oxygen:

One type the chemical name ends with “ite” as in hydrogen sulphite The other the chemical name ends with ”ate” as in hydrogen carbonate

for both there is NO ‘hydro’ in the name “ite” becomes ous ”ate” becomes ic

naming compounds names and formulas writing chemical formulas chemical formula: chemical formula: 1...

Documents

ionic charge

ion charge slide

naming ionic compounds

possible ion charge

polyatomic ions

oxygen atom ionic compounds

naming compounds names

total amt of charge