Chapter 2Chapter 2

Atoms, Molecules, and IonsAtoms, Molecules, and Ions

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Molecules and Molecular Molecules and Molecular CompoundsCompounds

A A diatomic moleculediatomic molecule is a molecule is a molecule that is made up of two atomsthat is made up of two atoms

A A molecular formulamolecular formula indicates the indicates the actual numbers and types of atoms actual numbers and types of atoms in a molecule.in a molecule.

An An empirical formulaempirical formula is the lowest is the lowest whole-number ratio of atoms in a whole-number ratio of atoms in a molecule. molecule.

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Molecules and Molecular Molecules and Molecular CompoundsCompounds

A A structural formulastructural formula of a of a substance shows which atoms are substance shows which atoms are attached to which within the attached to which within the molecule. molecule.

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Ions and Ionic CompoundsIons and Ionic Compounds

An ion with a positive charge is a An ion with a positive charge is a cationcation..

An ion with a negative charge is an An ion with a negative charge is an anionanion. .

A A polyatomic ionpolyatomic ion is a group of is a group of atoms joined as a molecule with an atoms joined as a molecule with an overall net charge.overall net charge.

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Ions and Ionic CompoundsIons and Ionic Compounds

An An ionic compoundionic compound is a compound is a compound that contains both positively and that contains both positively and negatively charged ions. negatively charged ions.

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Naming Inorganic Naming Inorganic CompoundsCompounds

Positive Ions (Cations)Positive Ions (Cations)

a) Cations have the same name as a) Cations have the same name as their metaltheir metal

b) If a metal can form different cations, b) If a metal can form different cations, the positive charge is indicated by a the positive charge is indicated by a Roman numeral in parentheses Roman numeral in parentheses following the name of the metalfollowing the name of the metal

Na+ sodium ion Zn2+ zinc ion Al3+ aluminum ion

Fe3+ iron(III) ion Fe2+ iron(II) ion Cu+ copper(I) ion Cu2+ copper(II) ion66

Names and Formulas of Names and Formulas of AcidsAcids

Acids of monatomic anions are called Acids of monatomic anions are called binary acidsbinary acids..Acids of oxyanions are called Acids of oxyanions are called oxyacidsoxyacids. . Binary AcidsBinary Acids OxyacidsOxyacids

HFHF hydrofluoric acid hydrofluoric acid HNOHNO3 3 nitric acidnitric acid

HClHCl hydrochloric hydrochloric acidacid

HH22SOSO44 sulfuric acidsulfuric acid

HBrHBr hydrobromic hydrobromic acidacid

HClOHClO44 perchloric perchloric acidacid

HH22SS hydrosulfuric hydrosulfuric HH22SOSO33 sulfurous acid sulfurous acid

HH22SeSe hydroselenic hydroselenic acidacid

HClOHClO33 chloric acid chloric acid

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Names and Formulas of Names and Formulas of AcidsAcids

To name binary acids replace the –ide ending To name binary acids replace the –ide ending with –ic acid and add the prefix hydro-with –ic acid and add the prefix hydro-

To name oxyacids, replace the –ate To name oxyacids, replace the –ate ending of the oxyanion with –ic acid or ending of the oxyanion with –ic acid or the –ite ending with –ous acidthe –ite ending with –ous acid

____ide become hydro____ic acid____ide become hydro____ic acid

Bromide, BrBromide, Br--, becomes hydrobromic acid, , becomes hydrobromic acid, HBrHBr

____ate becomes ____ic acid____ate becomes ____ic acid

Nitrate, NONitrate, NO33--, becomes nitric acid, HNO, becomes nitric acid, HNO33

____ite becomes ____ous acid____ite becomes ____ous acid

Sulfite, SOSulfite, SO332-2-, becomes sulfurous acid, , becomes sulfurous acid,

HH22SOSO33

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Names of Binary Molecular Names of Binary Molecular CompoundsCompounds

A binary molecular compound contains A binary molecular compound contains two nonmetals. The rules for naming two nonmetals. The rules for naming binary molecular compounds are:binary molecular compounds are:

1. Name the first element.1. Name the first element.

2. Name the second element giving it 2. Name the second element giving it an –ide ending.an –ide ending.

3. Use prefixes to denote how many 3. Use prefixes to denote how many of each element are in the formula.of each element are in the formula.

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Names of Binary Molecular Names of Binary Molecular CompoundsCompounds

PrefixPrefix MeaningMeaning

Mono-Mono- 11

Di-Di- 22

Tri-Tri- 33

Tetra-Tetra- 44

Penta-Penta- 55

Hexa-Hexa- 66

Hepta-Hepta- 77

Octa-Octa- 88

Nona-Nona- 99

Deca-Deca- 1010

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