Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Sep 24­10:24 AM

Chapter 2: Atoms, Molecules and Ions

Jun 15­2:23 PM

Natural Law ­ Law of Conservation of Mass• Established in 1789 by French Chemist Antoine Lavoisier• States that mass is neither created nor destroyed in any ordinary chemical reaction.• The mass of substances produced (products) by a chemical reaction is always equal to the mass of the reacting substances (reactants). • NO MASS IS GAINED OR LOST!

Example 2.2 A The Law of Conservation of MassIn a combustion reaction, 46.0 g of ethanol reacts with 96.0 g of oxygen to produce water and carbon dioxide. If 54.0 g of water is produced, how much carbon dioxide is produced?

2.2 Fundamental Chemical LawsObjectives:• The Law of Conservation of Mass• The Law of Definite Proportion• The Law of Multiple Proportions

2.1 The Early History of ChemistryThe Greek did not use experiments to establish the veracity of their ideas.Alchemy ­ "gold making juice"Khem the Egyptian word for black (the color of metals in preparation for alchemical treatment)

Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Sep 24­12:19 PM

The Law of Definite Proportion

a given compound always contains exactly the same proportion of elements by mass.

The law also applies to multiples of the fundamental proportion, for example:

Example 2.2 B The Law of Definite ProportionA sample of chloroform is found to contain 12.0 g of carbon, 106.4 g of chlorine, and 1.01 g of hydrogen. If a second sample of chloroform is found to contain 30.0 g of carbon, how many grams of chlorine and grams of hydrogen does it contain?

Sep 12­9:30 PM

The Law of Multiple Proportions

When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers

Example 2.2 C The Law of Multiple ProportionsWater H2O, contain 2.02 g of hydrogen and 16.0 g of oxygen. Hydrogen peroxide, H2O2, contains 2.02 g of hydrogen and 32.0 g of oxygen. Show how these data illustrate the law of multiple proportions.

Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Sep 24­12:22 PM

Example 2.3 Dalton’s Atomic TheoryMatch the chemical statement a­d below with Dalton's atomic theory statement below.Chemistrya. Although graphite and diamond have different properties (due to the nature of interatomic bonding), they are both composed solely of carbon. The carbon atoms are identical.b. 2H2O + O2 → 2H2O2, not CS2 or NaClc. There are 6.02 x 1023 atoms in 55.83 g of iron.d. C + O2 → CO2, CO2 is not CO, CO3 or Fe2O3

Dalton's Atomic Theories:1. Each element is made up of tiny particles called atoms.2. The atoms of a given element are identical; the atoms of different elements are different in some fundamental way or ways.3. Chemical compounds are formed when atoms combine with each other. A given compound always has the same relative number and types of atoms.4. Chemical reactions involve reorganization of the atoms ­ changes in the way they are bound together. The atoms themselves are not changed in a chemical reaction.

2.3 Dalton’s Atomic TheoryObjectives:• Ideas in Dalton's atomic theory that apply to specific chemical problems.

Sep 24­12:25 PM

2.4 Early Experiments to Characterize the Atom

Thomson's cathode­ray tube• all atoms must contain electrons• since atoms are known to be electrically neutral they must also contain some positive charge

Thomson's plum pudding model of the atom. The electrons are plums dispersed in a pudding

Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Sep 25­11:05 AM

Rutherford's gold foil experiment ­ explained the nature of the atom as having a small, dense, positively charged nucleus surrounded by electrons moving around it at a relatively large distance. Gold Foil experiment

(b) Actual Results(a) Expected Results of the Metal Foil Experiment if Thomson's Model Were Correct

Sep 25­11:14 AM

Example 2.5 Protons, Neutrons, Electrons, and Symbols

X = The element symbol, as read from the periodic tableZ = The number of protonsA = The number of protons + neutrons

Isotopes ­ atoms with the same number of protons but different numbers of neutrons

2.5 The Modern View of Atomic Structure: An IntroductionObjectives:• Assign the correct number of protons, neutrons, and electrons to an atoms• Write the symbol for an atom• Do the above operations for any isotopes of an atom

Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Sep 24­12:31 PM

2.6 Molecules and IonsObjectives:• Determine if a species is an atom, molecule, or ion• Determine the charge and the number of protons, neutrons, and electrons in monatomic ions.

Example 2.6 A Molecule, Atom or Ion?

Which of the following is an atom, an ion or a molecule?

C6H12 O6 _____________________________________

N2 _____________________________________

CO32­

_____________________________________

Ag _____________________________________

Fe3+ _____________________________________

NH4+ _____________________________________

Sep 24­12:35 PM

Example 2.6 B Protons, Neutrons, and Electrons in Ions

Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Sep 24­12:37 PM

2.7 An Introduction to the Periodic TableObjectives:• State whether an element is a metal or nonmetal and list what group it belongs to.• Look at the periodic table in this section of your textbook. Please note:1. The bold line from boron to polonium that separates metals from nonmetals2. Group names. You will be using these designations all year3. The various properties of each group, as described in the text4. Groups go down, periods go across

Example 2.7 Identify the ElementGiven the following information, identify each element.a. This is the only metal in Group 6Ab. This alkali metal is in the same period as iodinec. Two atoms of this element, which is in the same period as magnesium, combine with the magnesium ion to form a salt. Element Song

Periodic Table of Elements ­ Chemistry: A Volatile History ­ BBC Four

Element Song in Japanese

Feb 27­8:52 AM

A binary salt contains only one kind of cation (metal) and one kind of anion (nonmetal)

Rules for Naming Binary Ionic Compounds Containing a Metal Ion With a Fixed Charge

1. The cation is written first in the name; the anion is written second in the name.2. The name of the cation is the same as the (neutral) element from which it is derived.3. The anion is named by adding the suffix ­ide to the root of the element name.

Naming Binary Salts

ExamplesName the following binary compounds:a. KCl b. NaF c. CaCl2 d. BeO e. AlBr3 f. Al2O3

2.8 Naming Simple CompoundsObjectives:• Binary salts• Salts with polyatomic ions• Binary covalent compounds• Acids

Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Oct 1­8:41 AM

To determine the formula of binary ionic compounds remember that chemical compounds are electrically neutral. (The sum of the cation charges must equal the anion charges.)

WE WILL USE THE 7 STEPS CROSS­OVER RULE

Rules:1. Identify the substances as the metal and the nonmetal2. Write their symbols3. Write their charges (Check the periodic table)4. Cross­over the charges from top to bottom5. Remove the charge symbol (+ or ­)6. Simplify the numbers and remove the 1’s.7. Write the formula for the compound.

Writting Formulas for Binary Ionic Compounds

Oct 1­8:49 AM

Example: Formulas of Binary Ionic Compounds1. Determine the formula for each of the following sets of atoms when they combine to from a binary ionic compound.a. K and Brb. Sr and Fc. Al and Sed. Ba and O

a. Calcium Oxide b. Magnesium Chloridec. Barium fluorided. Potassium phosphidee. Sodium Sulfidef. Lithium oxide

2. Write the formula for the given names.

Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Oct 1 ­ 7:27 AM

For metals that can have more than one charge the name of the metal is succeeded by the Roman numerals in brackets

OR The Stock's System • by using the suffix ­ous for the lowest charge and ­ic for the highest charge and • sometimes with the Latinised name for the metal

Naming Binary Salts for Metals with more than one charge

Sep 24­12:46 PM

Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Oct 1­9:00 AM

a. Iron III sulfide

b. Iron II Sulfide

c. Copper I chloride

d. Copper II chloride

ExamplesName the following compounds:

2.8 C ExamplesWrite the formula for the given names.

a. CuF2

b. CuBr

c. HgO

d. PbO

e. PbO2

f. CuCl2

g. SnCl4

h. FeF3

i. Co2O3

j. Mn 2O7

Oct 1­9:06 AM

Ternary compounds are compounds that consist of more than two elements. In naming and writing the formulae for ternary compounds, we follow rules that are similar to binary compounds.

Naming Ternary Salts

Rules for Naming Ternary Salts: 1. Decide if the metal is a metal with fixed or variable charge. 2. Name the metal, following the rules in naming for: * metal with fixed ionic charge, or * metal with variable charge (roman #) 3. Name the metal followed by the name of the polyatomic anion . 4. For compounds containing NH4+ cations: * Name the cation first followed by the anion (remember that for

simple anion, the ending is in ­ide ).

Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Sep 24­12:48 PM

Example 2.8 D Naming Compounds with Polyatomic Ions

Name the following compounds:

a. KMnO4

b. Ba(OH) 2

c. Fe(OH) 3

d. NaH 2PO4

e. (NH 4)2Cr2O7

f. NaBrO 3

g. KIO 3

h. Ca(OCl) 2

i. Cr(NO 3)3

Oct 1­9:13 AM

Witting Formulas for Ternary Salts:WE WILL USE THE 8 STEPS CROSS­OVER RULE

Rules:1. Identify the substances as the metal and the polyatomic ion2. Write their symbols3. Write their charges 4. Cross­over the charges from top to bottom.5. Remove the charge symbol (+ or ­)6. If more than one polyatomic ion is used place ( ) around it. Write a subscript after the ( )x7. Simplify the numbers and remove the 1's.8. Write the formula for the compound.

ExamplesWrite the formula for the given names.a. lithium carbonateb. calcium nitrate c. sodium sulfated. barium hydroxidee. Iron II phosphate

Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Sep 24­12:46 PM

Example 2.8 E Naming Binary Covalent Compounds Name the following compounds:

a. CO2

b. P 2O5

c. N 2O3

d. Cl 2O7

e. SO 3

f. BrF 3

Example 2.8 F Naming Acids

Name the following acids:

a. HF

b. HC2H3O2

c. HBrO 3

d. HBrO

e. HI

f. HNO 2

Sep 24­12:46 PM

Example 2.8 F Trying it all TogetherName the following compounds:

a. PCl5

b. HClO 2

c. Ni(NO 3)2

d. Sb 2S3

e. XeF 4

f. NH 4OH

g. NaC2H3O2

h. NaHCO 3

i. LiH

Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Sep 24­12:44 PM

Example 2.8 H Formulas from Names

Write the formulas for each compounds:

a. sodium chloride

b. calcium chloride

c. iron(III) nitrate

d. copper (I) chloride

e. hypoiodous acid

f. tin(IV) oxide

g. dinitrogen tetroxide

h. ammonium acetate

Sep 22­10:09 PM

Naming HydratesThere are many solid compounds that release water when heated at fairly low temperatures. In these compounds the water molecules are loosely bonded within the solid crystal at regular intervals.

The table shows the prefixes which are used to indicate the number of water molecules.Practice

Chapter 2 Atoms, Molecules and Ions.notebook

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September 10, 2015

Oct 1 ­ 7:28 AM

Naming HydrocarbonsAlkanesHydrocarbons having single bond functional groups are classified as alkanes where the carbon atoms of the molecule are arranged in chains.

• These formulas all fit the CnH2n+2 rule. This is also the highest possible H/C ratio for a stable hydrocarbon. • Since the H/C ratio in these compounds is at a maximum, we call them saturated (with hydrogen).

Oct 1 ­ 7:28 AM

Alkenes and AlkynesAlkenes and alkynes are hydrocarbons which respectively have carbon­carbon double bond and carbon­carbon triple bond functional groups. The molecular formulas of these unsaturated hydrocarbons reflect the multiple bonding of the functional groups:

AlcoholsAll Alcohols contain the hydroxyl functional group, ­O­H, attached to single bonded hydrocarbons (alkanes). Alcohol has the general formula R­OH where R represents any chain of carbon and hydrogen atoms. The four most common Alcohols are:

CH3OH Methanol CH3CH2OH Ethanol CH3CH2CH2OH Propanol