compounds and nomenclature. bonding & stability atoms want to be stable. the octet rule states...

Compounds and Nomenclature

Bonding & Stability Atoms want to be stable. The Octet Rule states that a chemically stable

atom contains 8 valence electrons.

Chemical Bonds Atoms will gain, lose, or share electrons to obtain 8

valence electrons – this is called a chemical bond There are 3 types of bonds:

Metallic Ionic Covalent / Molecular

Ionic Bonds

Types of Compounds1. Ionic Compounds:- involve the transfer of electron(s) between 2

oppositely charged ions (cation and anion)- metal and a nonmetal or a combination involving a

complex ion- forms an ionic bond - exists as an ionic crystal lattice (not individual

molecules)- known as a formula unit (eg. A formula unit of salt,

not a molecule)

Crystal Lattice

Formula Unit a chemical formula showing the simplest

whole number ratio of cations to anions in an ionic compound.

Eg. NaCl – sodium chloride

Types of Compounds (continued)2. Molecular compounds:

- involve the sharing of electrons between nonmetals

- forms a covalent bond- exists as individual molecules- Eg. Carbon dioxide CO2

water H2O

Covalent Bond/Molecule

Ionic and Covalent Bonds

Properties of Ionic and Molecular Compounds

1. State at room temperature:- all ionic compounds are solids- molecular compounds may be a solid, liquid or a gas

2. Conductivity of solution:- ionic compounds conduct electricity (electrolytes)- molecular compounds do not conduct electricity (non- electrolytes)

3. Solubility in water:- ionic compounds are soluble, to varying degrees (some better than others) and form colored or colorless solutions.- molecular compounds may or may not be soluble (colorless solutions if they form).

Nomenclature Chemical nomenclature is the systematic

naming of chemical compounds. Science 1206 examines the naming of ionic

compounds, molecular compounds and acids. Compounds can be divided into two basic

categories, those which are true binary compounds (contain only two types of elements), and those which contain more than two different types of elements.

Is there a metal or ammonium in the formula?







Ionic compoundsIdentify the type of ions:

A. Monoatomic or simple ions

B. Polyatomic or complex ions

C. Multivalent ions

D. Hydrates

Rules for Naming ionic compounds:

A. Monoatomic or simple ions Single atoms that have lost or gained one or

more electrons Form binary ionic compounds (2 simple ions) Consist of cations and anions Eg. Sodium + chlorine Na+ Cl-

Cations are written first, anions are second (name changes to “-ide” for the anion)

The total charge must be zero Do not write charges in your final answer

Rules for formulas:

a. Write the symbols for the ions involved:

eg. Silver and chlorine

Ag+ and Cl-

Rules:

b. Determine the lowest whole number ratio of ions which will provide an overall net charge of zero

Ag1+ Cl1- becomes AgCl

(silver chloride)

Example: potassium and oxygen

potassium - K+

oxygen - O2-

K2+ O1

2-

becomes K2O potassium oxide

Practice – Writing FormulasWrite formulas for the following compounds:

Lithium bromide

Potassium chloride

Barium chloride

Magnesium nitride

Aluminum Fluoride

Calcium Nitride

Naming Ionic Compounds Cation is named first Anion is named second Ending of anion is changed to “ide”

Practice:

NaCl BaCl2 Al2O3

B. Multivalent ions

- certain transition metals can form more than one type of ion, each with a different charge.

- eg. Cu2+ - copper (II)

Cu+ - copper (I)

Multivalent ions (continued) The transition metals have various electron

configurations that will make them stable Use a roman numeral after the cation to

specify its charge (Stock naming system). Eg. Iron (ii) oxide FeO

Iron (iii) oxide Fe2O3

Stock vs. ClassicalFormula Stock Name Classical Name Cu+ copper(I) ion Cuprous ion Cu2+ copper(II) ion Cupric ion Fe2+ iron(II) ion Ferrous ion Fe3+ iron(III) ion Ferric ion

- the one written on top is the more common ion

- eg. Fe3+ - iron (III)

Fe2+ - iron (II)

Practice:CuSO4

PbO

uranium (vi) oxide

uranium (iv) oxide

C. Polyatomic/Complex Ions Polyatomic ion: atoms of 2 or more elements

covalently bonded together with an overall chargeeg. Nitrate NO3

-

Ammonium NH4+

Complex ions are groups of atoms that are made stable by sharing electrons and which then become even more stable by gaining (usually) or losing electrons.

The total positive charge in the formula must be equal to the total negative charge.

Rules: Name the cation, then name the anion Don’t change the ending of a polyatomic ion! Balance the charges If you need more than 1 complex ions, use

brackets for that group

Practice

NaNO3

Al2(SO4)3

Mg(OH)2

NaCH3COO

D. Hydrates Ionic compounds that contain water in their

structure eg. CuSO4 H2O

Hydrate - Rules Name the ionic part of

the formula first Name the water part

second using a prefix system for the number of water molecules

Add prefix to “hydrate”

Prefixes:

1. mono

2. di

3. tri

4. tetra

5. penta

6. hexa

7. hepta

8. octa

9. nona

10. deca

Example:CuSO4 5H2O

Copper (II) sulfate pentahydrate

Review1. Silver nitrate 12. Copper(II) sulfate2. Iron(II) phosphate 13. Cobalt(II) iodide3. Chromium(III) oxide 14. Cesium phosphate4. Nickel(II) fluoride 15. Magnesium acetate5. Copper(I) nitrate heptahydrate 16. Potassium oxide6. Lead(II) carbonate 17. Strontium nitrate7. Iron(II) fluoride 18. Aluminum sulfate8. Iron(III) hydroxide 19. Calcium chlorate9. Zinc phosphate dihydrate 20. Rubidium cyanide10. Potassium chlorate 21. Tin(IV) oxide11. Ammonium chromate 22. Titanium(II) iodide

Ionic Formulas1. BaCl2 10. FeCl3

2. Pb(NO3)2 11. Ca(CN)2

3. TiI3 12. Cu2S

4. K2CrO4 14. Cd(ClO)2

5. CoO 15. SnO2

6. Mg(ClO4)2 16. NaHCO3

7. CuSO4 17. Al(C2H3O2)3

8. Na2SO3 18. Ni3(PO4)2

Molecular CompoundsChemical Bonding

NO!!!!!!!!!

Molecular Compounds

Binary molecular compounds form between 2 non-metals

Covalent bonds: shared electrons Molecular formula: shows number and kind

of atoms in a molecule

Naming Use prefixes to specify

number of atoms of each element in the molecule

Second element ends with “-ide”

No charges used in formula The prefix “mono-” should

not be used on the first element

1. mono

2. di

3. tri

4. tetra

5. penta

6. hexa

7. hepta

8. octa

9. nona

10. deca

Practice Name the following:

NO CO2

N4O9

N6O

Write formulas for the following: Boron trifluoride Sulfur hexafluoride Nitrogen monoxide Phosphorous

pentachloride

ACIDS HCl Hydrochloric Acid H2SO4 Sulfuric Acid

HNO3 Nitric Acid

HC2H3O2 Acetic Acid

H3PO4 Phosphoric Acid

H2CO3 Carbonic Acid

Acids have 2 criteria:1. They must contain hydrogen (H+)

2. They must be dissolved in water (aqueous); the formula will always contain the subscript aq.

Naming AcidsHydrogen is always the positive ion for an acid Ending Acid Name Example

1. -ide begins with hydro, HCl

ends with -ic and acid

2. –ite ends with –ous and acid H2SO3

3. –ate ends with –ic and acid H2SO4

compounds and nomenclature. bonding & stability atoms want to be stable. the octet rule states...

Documents

naming of ionic compounds

naming ionic compounds

types of compounds

o slide

binary ionic compounds

nomenclature slide

following compounds

solids molecular compounds