© 2003 mark s. davis ap chemistry chapter 2. © 2006 mark s. davis 5

© 2003 Mark S. Davis

AP Chemistry

Chapter 2


5


•http://dbhs.wvusd.k12.ca.us/webdocs/ChemTeamIndex.html


• A man was out walking in the desert when a voice said to him, "Pick up some pebbles and put them in your pocket, and tomorrow you will be both happy and sad."

• The man obeyed. He stooped down and picked up a handful of pebbles and put them in his pocket. The next morning he reached into his pocket and found diamonds and rubies and emeralds. And he was both happy and sad. Happy he had taken some - sad that he hadn't taken more.

• And so it is with education


Atomic Theory of Matter

• Dalton’s Postulates1. Each element is composed of

extremely small particles called

2. All atoms of a given element are identical; the atoms of different elements are different and have different properties (including different masses.)


Dalton

3. Atoms of an element are not changed into different types of atoms by chemical reactions; atoms are neither created nor destroyed

4. Compounds are formed when atoms of more than one element combine; a given compound has the same relative number and kinds of atoms.


Define

• Atom:–

• Element:–


Define• Compounds:

– Substance composed

• Mixtures:– Combination of two or more

• Law of conservation of Mass:


Atomic Structure

• Protons:–

• Neutrons:–

• Electrons:– – Charge is 1.6 x 10-19C


Atomic Numbers

• Tell you:– Number of – Number of


Atomic Weights

• Atomic mass units (amu)

• 1 amu = 1.66054 x 10-24 g

• 1 g = 6.022137 x 1023 amu

• Mass on the table– 1 C = 12 amu


Average Mass

• Isotopes

• Ave mass = (mass x %) + (mass x %)

• C has two isotopes– C-12 at 98.93%– C-13 at 1.07 %– Determine the average atomic mass


The Periodic Table

• Family/Group–

• Period–

• Isotopes


Types of elements

• Alkali Metals

• Alkaline Earth Metals

• Transition Metals

• Metalloids

• Non-metals

• Noble Gases

• Halogens

• Chalcogens

• Pnictides

• F-block

• Transuranium


Molecules and Ions

• Molecule:– Chemically combined elements

•

• Diatomic Molecule

•


Formulas

• Molecular–

• Empirical–

• Structural–


IONS

• Cation:–

• Anion:–

• Polyatomic:–


Predicting Charges

• Based on the Periodic Table• Na• Br• O• Ca• Al• Si


Ionic Compounds

• Contain cations and anions–

• Use ELECTRONEGATIVITY to determine whether a compound is ionic–


Ionic Compounds

• Most ionic compounds can only be represented by empirical formulas–

• Writing formulas for ionic compounds– – –


Nomenclature

• System to ‘easily’ name chemical compounds.

• Organic, rules, rules, rules… – Ethane, ethanol, dimethyl ether

• Inorganic – much simpler


Ionic Naming

• Look at Periodic Table… Oxidation number

• Cations with one possible charge keep name– – – –


Ionic Naming

• Look at Periodic Table… Oxidation number

• Cations with more than one possible charge– – –

• Use the Stock System


Stock System

• Use a Roman Number, I, II, III, IV, V, VI to represent the oxidation number

•

• Cr+3

• Copper (I)


Anions

• Monatomic:–Ending is changed to

• Polyatomic: some have –ide ending–CN-

–OH-


Practice

• Write the formula for the following:–

–


Oxyanions

• Oddly enough… contain oxygen!–Ending is changed to:

• -ate • -ite

• Chlorine series


Practice

• Name the following–

–

–


Acids• Defined:

– Donate a proton

• Anion needs to be balance by hydrogen

• KNOW THE SIX STRONG ACIDS


Binary MOLECULAR Compounds

• Characterized by covalent bonds, not ionic

• Use prefixes mono-, di-, tri-, etc…

• More positive element named first

• Second element has –ide ending


Practice

• Name the following– – –

© 2003 mark s. davis ap chemistry chapter 2. © 2006 mark s. davis 5

Documents

number of number

mass x

atoms of different elements

given element

different types of atoms

firstsecond element

kinds of atoms

chemical reactions atoms