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Home , Chemical nomenclature

Atoms, , &

Chapter 2 The Early - Before 16th Century : Attempts (scientific or otherwise) to change cheap into gold - 17th Century Robert Boyle: First “chemist” to perform quantitative experiments - 18th Century George Stahl: Phlogiston flows out of a burning material. Joseph Priestley: Discovers gas, “dephlogisticated air.” Law of Conservation of Mass

- Discovered by

- Mass is neither created nor destroyed

- Combustion involves oxygen, not phlogiston Other Fundamental Chemical Laws

Law of Definite Proportion -- Joseph Proust

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

- Carbon tetrachloride is always 1 atom carbon per 4 atoms . Other Fundamental Chemical Laws

Law of Multiple Proportions--John Dalton

- 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.

- The ratio of the masses of oxygen in H2O and H2O2 will be a small whole number (“2”). Dalton’s Atomic Theory (1808)

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. Dalton’s Atomic Theory (continued)

3 Chemical compounds are formed when atoms combine with each other. A given compound always has the same relative numbers 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. Avogadro’s Hypothesis (1811)

At the same temperature and pressure, equal volumes of different gases contain the same number of particles.

5 liters of oxygen 5 liters of Same number of particles! 02_17

+

2 volumes combines with 1 volume to form 2 volumes oxygen gaseous

+

1 volume combines with 1 volume to form 2 volumes hydrogen chlorine hydrogen

A representation of some of Gay-Lussac’s experimental results on combining gas volumes. 02_18

H H

H H H H + O O O O

H H

H H + Cl Cl H Cl H Cl

A representation of combining gases at the molecular level. The spheres represent atoms in the molecules. Evidence for the HOFBrINCls. Chemical Symbols

The chemical symbols used today were developed by Jons Jakob Berzelius. They consist of one or two letters. The first letter is always capitalized. The second, if there is one, is never capitalized. The second letter is often a letter prominent in the pronunciation. Early Experiments to Characterize the Atom

- J. J. Thomson - postulated the existence of electrons using cathode ray tubes. - Ernest Rutherford - explained the nuclear atom, containing a dense nucleus with electrons traveling around the nucleus at a large distance. 02_21

Applied electric field (+)

(-)

Metal (+) electrode (-) electrode

Deflection of cathode rays by an applied electric field. 02_23

Oil spray

Atomizer to produce oil X rays produce droplets charges on the oil drops (+)

Microscope

Electrically charged plates (-)

Schematic representation of the apparatus that Millikan used to determine the charge on the electron -- the oil-drop experiment. 02_24

Some alpha Most particles particles are pass straight Uranium source of scattered through foil alpha particles (embedded in a to absorb most of the radiation)

Thin Beam of metal foil alpha particles Luminescent screen to detect scattered alpha particles

Rutherford’s experiment of alpha particle bombardment of gold foil. 02_25

Electrons scattered throughout Diffuse positive - charge ------

n+ ------

(a) (b)

a) the expected results of the gold foil experiment if Thomson’s Plum Pudding Model were correct b) the actual results. The Modern View of Atomic Structure

The atom contains: - electrons - protons: found in the nucleus, they have a positive charge equal in magnitude to the electron’s negative charge. - neutrons: found in the nucleus, virtually same mass as a proton but no charge. The Mass and Charge of the Electron, Proton, and Neutron

Particle Mass (kg) Charge

Electron 9.11  10−31 1−

Proton 1.67  10−27 1+

Neutron 1.67  10−27 0 The Chemists’ Shorthand: Atomic Symbols

Mass number → 39  Element Symbol Atomic number → 19 K A = Z + N

A = mass number ( from German Atomgewicht) Z = atomic number ( from German Zahl) N = number of neutrons

A = Z + N Chemical Bonds

The forces that hold atoms together in compounds. Covalent bonds result from atoms sharing electrons. : a collection of covalently-bonded atoms. The Chemists’ Shorthand: Formulas : Symbols = types of atoms Subscripts = relative numbers of atoms

CO2 : Individual bonds are shown by lines. O=C=O Ions Cation: A positive 2+ + Mg , NH4 Anion: A negative ion − 2− Cl , SO4 Polyatomic: an ion containing a number of covalently bonded atoms acting as a single unit.

Ionic Bonding: Force of attraction between oppositely charged ions. Cations & Anions

Cations are positive ions. Na ----> Na+ + e-

Anions are negative ions. - - Cl2 + 2e ----> 2Cl Elements classified by: - properties - atomic number

Groups (vertical) 1A = alkali metals 2A = alkaline earth metals 7A = 8A = noble gases

Periods (horizontal) 02_29 Noble Alkaline gases earth metals 1 Halogens 18 1A 8A

1 2 H 2 13 14 15 16 17 He 2A 3A 4A 5A 6A 7A

3 4 5 6 7 8 9 10 Li Be B C N O F Ne

11 12 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Na Mg Transition metals Al Si P S Cl Ar

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Alkalimetals

55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Cs Ba La* Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

87 88 89 104 105 106 107 108 109 110 111 Fr Ra Ac† Unq Unp Unh Uns Uno Une Uun Uuu

58 59 60 61 62 63 64 65 66 67 68 69 70 71 * Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

90 91 92 93 94 95 96 97 98 99 100 101 102 103 † Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

The periodic table. Chemical Symbols

Symbols commonly missed. • A -- Al, Ar, As, Au, & Ag. • B -- Ba, Bi, B, Br, & Be. • C -- C, Ca, Cd, Cl, Cr, Co, Cs, & Cu. • M -- Mg, Mn, & Mo. • S -- S, Sb, Si, Sr, & Sn. • Latin -- Fe, Au, Ag, Sb, Pb, Na, K, Hg, & Cu. • German -- W Physical Properties of Metals

Metals are: 1. efficient conductors of heat and electricity. 2. malleable (Can be hammered into thin sheets). 3. ductile (Can be pulled into wires). 4. lustrous (shiny). 5. tend to lose electrons and form cations. Examples are: Na, Cu, Au, Ag, & Fe. • substances with the properties of both metals and . • also called semimetals • Lie along the zigzag line between metals and nonmetals • The six metalloids are: B, Si, Ge, As, Sb, and Te. Physical Properties of Nonmetals Nonmetals are: 1. nonconductors of heat and electricity (insulators). 2. not malleable, but are brittle. 3. not ductile. 4. dull and without a luster. 5. tend to gain electrons to form anions. Examples are: H, He, N, O, S, & P. The Chemists’ Shorthand: Atomic Symbols

Mass number → 39 1+  Ion charge  Element Symbol Atomic number → 19 K METALS M ---> Mn+ + n e- where n = periodic Na ---> Na+ + e- Mg ---> Mg2+ + 2 e- Al ---> Al3+ + 3 e- Transition metals --> M2+ or M3+ are common NONMETALS

NONMETAL + n e------> Xn- where n = 8 - Group # C + 4 e- ---> C4- C4- carbide N + 3 e- ---> N3- N3- nitride O + 2 e- ---> O2- O2- oxide F + e- ---> F1- F- Charges on Common Ions -4 -3 -2 -1 +1

+2 +3 A = Z + N

z # protons # electrons # neutrons 35 0 17 Cl 17 17 17 18

35 1- 17 17 18 18 17 Cl Common Names sugar of lead lead(II) blue vitriol copper(II) quicklime Epsom salts milk of magnesia magnesium gypsum calcium sulfate laughing gas dinitrogen monoxide Naming Compounds

Binary Ionic Compounds: 1. Cation first, then anion

2. Monatomic cation = name of the element Ca2+ = calcium ion

3. Monatomic anion = root + -ide Cl− = chloride

CaCl2 = Naming Compounds (continued) Binary Ionic Compounds (Type II):

- metal forms more than one cation - use Roman numeral in name

PbCl2 Pb2+ is cation

PbCl2 = lead (II) chloride plumbous chloride Naming Compounds (continued) Binary compounds (Type III):

- Compounds between two nonmetals - First element in the formula is named first. - Second element is named as if it were an anion. - Use prefixes - Never use mono-

P2O5 = pentoxide Must Knows

• Table 2.3 on page 61. • Table 2.4 on page 62. • Table 2.5 on page 66. • Table 2.6 on page 67. • Table 2.7 on page 71. • Table 2.8 on page 71. NOMENCLATURE OF COMPOUNDS Binary -- 2 elements Ternary -- (3 elements) - Ionic (metal ion + )

Type I - Ionic Ca3(PO4)2 -- calcium (Type I metal + ) FeSO4 -- (II) sulfate Group I, II, Al+3, Ag1+, -- ferrous sulfate Cd2+, & Zn2+ NaCl -- Chloride

Type II - Ionic (Type II metal + nonmetal) All other metals

Fe2S3 -- iron (III) Type III - covalent -- ferric sulfide (2 nonmetals) CO2 -- Chemical Nomenclature

Name each of the following: CuCl copper(I) chloride cuprous chloride HgO mercury(II) oxide mercuric oxide iron(III) oxide ferric oxide Fe2O3

MnO2 manganese(IV) oxide manganic oxide

PbCl2 lead(II) chloride plumbous chloride

CrCl3 chromium(III) chloride chromic chloride Chemical Nomenclature

Name each of the following:

P4O10 tetraphosphorus decoxide

N2O5

Li2O2 lithium peroxide

Ti(NO3)4 titanium(IV)

SO3

SF6

O2F2 Common Nomenclature Mistakes Compounds: Polyatomic ions:

2- SO3 --Sulfur trioxide SO3 -- Sulfite ion 1- NO2 -- Nitrogen NO2 -- ion dioxide 1- NO3 -- Nitrate ion NO3 -- Nitrogen trioxide 02_33

Does the anion contain oxygen?

No Yes

hydro - Check the ending of the anion. + anion root + -ic hydro (anion root)ic acid -ite -ate

anion or element root anion or element root + -ous + -ic (root)ous acid (root)ic acid

A flow chart for naming acids. An acid is best considered as one or more H+ ions attached to an anion. Binary Acids

• made up of two elements -- hydrogen and a nonmetal • named by using: prefix hydro + root of nonmetal + ic + acid

HCl --

H2Se -- hydroselenic acid Ternary Acids ()

• contain three elements -- hydrogen, nonmetal, and oxygen. • most oxygen per + root of nonmetal + ic + acid • less oxygen root of nonmetal + ic + acid • less oxygen root of nonmetal + ous + acid • least oxygen hypo + root of nonmetal + ous + acid Ternary Acids (continued)

HBrO4 perbromic acid

HBrO3 bromic acid

HBrO2 HBrO hypobromous acid

H3PO4

H3PO3

H3PO2 hypophosphorus acid Salt Nomenclature (Ionic compounds)

Binary salts (metal and nonmetal) name of positive ion + root of nonmetal + ide

NaCl --

K2S -- potassium sulfide Salt Nomenclature (continued) Ternary salts ( metal and polyatomic ion) name of positive ion + root of nonmetal + ate or ite If the salt comes from an ic acid, change ic to ate.

H2CO3 Na2CO3 sodium

H3PO4 phosphoric acid K3PO4 potassium phosphate

If the salt comes from an ous acid, change ous to ite.

H2SO3 Li2SO3 HClO NaClO sodium