chapter 2 atoms and elements. dalton’s atomic theory ( beginning of 19 th century ) all matter is...

Chapter 2Chapter 2

Atoms and ElementsAtoms and Elements

Dalton’s Atomic TheoryDalton’s Atomic Theory((beginning of 19beginning of 19thth century century))

• All matter is composed of tiny, All matter is composed of tiny, indivisible indivisible particles called atoms particles called atoms

• All atoms of a given element are All atoms of a given element are identical to each other and different identical to each other and different from those of other elementsfrom those of other elements

• A chemical reaction merely involves A chemical reaction merely involves a change in the groupings of atoms a change in the groupings of atoms and not creation or destruction of and not creation or destruction of atoms (Law of Conservation of Mass)atoms (Law of Conservation of Mass)

• Compounds consist of atoms of Compounds consist of atoms of more than one element combined in more than one element combined in particular ratios (Law of Constant particular ratios (Law of Constant Composition and Law of Multiple Composition and Law of Multiple Proportions)Proportions)

Building up Atomic StructureBuilding up Atomic Structure• Benjamin Franklin (1706-1790) discovered two Benjamin Franklin (1706-1790) discovered two

types of electricity, (+) and (-). types of electricity, (+) and (-). • Henri Becquerel discovered radioactivity on 1896. Henri Becquerel discovered radioactivity on 1896.

Pierre and Marie Curie continued that work: Pierre and Marie Curie continued that work: atoms disintegrate, i.e., they are atoms disintegrate, i.e., they are divisibledivisible..

• John J. Thomson discovered the John J. Thomson discovered the electronelectron and and determined its charge/mass ratio (1896-97).determined its charge/mass ratio (1896-97).

• Robert A. Millikan (1909) determined the charge Robert A. Millikan (1909) determined the charge and mass of electron.and mass of electron.

• Ernest Rutherford (1911-19) discovered the Ernest Rutherford (1911-19) discovered the protonproton..

• James Chadwick (1932) discovered the James Chadwick (1932) discovered the neutronsneutrons, , that are with the protons in the that are with the protons in the nucleusnucleus of atoms. of atoms.

Atomic StructureAtomic Structure

• subatomic particlessubatomic particles neutronneutron: no charge, 1.0087 amu, n: no charge, 1.0087 amu, n protonproton: +1 charge, 1.0073 amu, p: +1 charge, 1.0073 amu, p++

electronelectron: –1 charge, 0.0005486 amu, e: –1 charge, 0.0005486 amu, e––

• n and pn and p++ packed tightly into dense core packed tightly into dense core called called nucleusnucleus

• ee–– distributed more diffusely in space distributed more diffusely in space surrounding nucleussurrounding nucleus

e–

np+

e–Actual size: Radius of atom ~ 100 pm (10-10 m)Radius of nucleus ~ 0.001 pmThen, if radius of atom was ~ 100 m (a small football stadium), the radius of the nucleus would be ~ 0.001 m = 1 mm V r3 Then, Vatom/Vnucleus 1015. Atom is 1015 times bigger

• all atoms of a given element have the all atoms of a given element have the same number of protonssame number of protons

• number of protonsnumber of protons in an atom given by in an atom given by the the atomic numberatomic number, Z, Z

• neutral atoms have same number of neutral atoms have same number of protons and electronsprotons and electrons

• atoms gain or lose charge by gaining or atoms gain or lose charge by gaining or losing electrons only (not protons)losing electrons only (not protons)

• total number of protons and neutrons total number of protons and neutrons given by given by mass number, A. A = #pmass number, A. A = #p++ + #n + #n

Atomic number and Mass number

SymbolSymbol

XXZZ

AA nn

atomic numberatomic number

chargecharge

element symbolelement symbol

mass numbermass number

ExamplesExamples

Determine the numbers of electrons, Determine the numbers of electrons, protons, and neutrons in each of the protons, and neutrons in each of the following atoms.following atoms.

ArAr4040

1818

Z = 18, therefore the atom has 18 pZ = 18, therefore the atom has 18 p++

A = 40, A = 40,

A = # of pA = # of p++ + # of neutrons + # of neutrons

Therefore, # neutrons = A Therefore, # neutrons = A − # p− # p++

40 – 18 = 22 neutrons40 – 18 = 22 neutrons

Charge, n = 0, therefore # of eCharge, n = 0, therefore # of e–– = # p = # p++ = 18 = 18

ArAr4040

1818

PbPb209209

8282

2+2+

• Z = 82, therefore 82 pZ = 82, therefore 82 p++

• A = 209, therefore 209 pA = 209, therefore 209 p+ + and n totaland n total

• # neutrons = A # neutrons = A − # p− # p++ = 209 – 82 = 127 n = 209 – 82 = 127 n

• n = 2+, n = 2+,

• Therefore # eTherefore # e–– = 82 p = 82 p++ − 2 =− 2 = 80 e 80 e–– ( (lost 2 elost 2 e––))

PP3131

15153–3–

Z = 15, therefore 15 pZ = 15, therefore 15 p++

PP3131

15153–3–


A = 31, therefore 31 pA = 31, therefore 31 p++ and n total and n total

PP31311515

3–3–



31 – 15 = 16 n31 – 15 = 16 n

PP3131

1515

3–3–



31 – 15 = 16 n31 – 15 = 16 n

n = 3 –, (gained 3 en = 3 –, (gained 3 e––))

Therefore, # eTherefore, # e−− = 15 + 3 = 18 e = 15 + 3 = 18 e−−

PP3131

15153–3–

IsotopesIsotopes

• atoms (of same element) that have atoms (of same element) that have the same number of protons but the same number of protons but different numbers of neutrons, i.e., different numbers of neutrons, i.e., different different AA

• may or may not have same number may or may not have same number of electronsof electrons

XX52522424 XX

55552424

XX52522424 XX

55552424

XX52522424 XX

52522020

XX5252

2424XX

5555

2424

XX5252

2424 XX5252

2020

XX5252

2424XX

5050

2424

3+3+

Which of the Which of the pairs of atoms pairs of atoms

is(are) is(are) isotope(s)?isotope(s)?

Isotope abundanceIsotope abundanceA sample of naturallyA sample of naturallyoccurring sulfur containsoccurring sulfur containsseveral isotopes with theseveral isotopes with thefollowing abundancesfollowing abundances

Isotope % abundanceIsotope % abundance 3232S S 95.02 95.02 3333SS 0.75 0.75 3434S S 4.21 4.21 3636SS 0.02 0.02

The %s have been determined experimentally.The %s have been determined experimentally.

# of atoms of a given isotope# of atoms of a given isotope% Abundance = % Abundance = ──────────────────────────────────────────────────────── x 100 x 100 Total # of atoms of all isotopes of element Total # of atoms of all isotopes of element

32S, 33S, 34S, 36S16 16 16 16

Mass Spectrometry is employed to Mass Spectrometry is employed to determine Isotopic Abundancesdetermine Isotopic Abundances

• mass spectrometer.mass spectrometer.– Device generates ions that pass down an Device generates ions that pass down an

evacuated path inside a magnet.evacuated path inside a magnet.– Ions are separated based on their Ions are separated based on their

charge/mass ratio. Mass is, then, calculated.charge/mass ratio. Mass is, then, calculated.

Atomic WeightAtomic Weight

The atomic mass and Isotope Abundances areThe atomic mass and Isotope Abundances aredetermined by means of determined by means of Mass SpectrometryMass Spectrometry..

Atomic mass of isotope Atomic mass of isotope carbon-12 is defined exactly 12 carbon-12 is defined exactly 12 amuamu whereas all others of carbon and other elements whereas all others of carbon and other elementsare referred to that and do not have integer values.are referred to that and do not have integer values.

% abundance isotope 1Atomic weightAtomic weight = = x (mass isotope 1) x (mass isotope 1) 100100

% abundance isotope 2 % abundance isotope 2 + + x (mass isotope 2) + … x (mass isotope 2) + … 100100

ExampleExample

Isotope % abundanceIsotope % abundance mass (amu)mass (amu)6464 Zn Zn 48.6 48.6 63.9291 63.92916666ZnZn 27.9 27.9 65.9260 65.92606767ZnZn 4.1 4.1 66.9721 66.97216868ZnZn 18.8 18.8 67.9249 67.92497070ZnZn 0.6 0.6 69.9253 69.9253

Example, contd.Example, contd.

%abund.%abund.ii

Atomic weight of Atomic weight of ZnZn = = ∑∑ m mii

100100

A.W.= 0.486 A.W.= 0.486 63.9291 + 0.279 63.9291 + 0.279 65.9260 + … 65.9260 + …

+ 0.041 + 0.041 66.9721 + 0.188 66.9721 + 0.188 67.9249 + … 67.9249 + …

+ 0.006 + 0.006 69.9253 = 69.9253 = 65.4 amu65.4 amu

# 25. Gallium has two naturally occurring isotopes, # 25. Gallium has two naturally occurring isotopes, 69Ga and 71Ga, with masses of 68.9257 amu and 69Ga and 71Ga, with masses of 68.9257 amu and 70.9249 amu, respectively. Calculate the % abundance 70.9249 amu, respectively. Calculate the % abundance of the two isotopes of Ga. of the two isotopes of Ga. A W Ga = 69.723 (Per. table)A W Ga = 69.723 (Per. table)

Let’s name p1 = % of 69Ga and p2 = % of 71Ga.Let’s name p1 = % of 69Ga and p2 = % of 71Ga.p1 + p2 = 100 then, p1 = 100 − p2 p1 + p2 = 100 then, p1 = 100 − p2 (1)(1)

p1 p1 68.9257 + p2 68.9257 + p2 70.9249 70.9249AW = 69.723 = ──────────────────── then,AW = 69.723 = ──────────────────── then, 1001006972.3 = p16972.3 = p168.9257 + p268.9257 + p270.9249 Then, replace p1 by 70.9249 Then, replace p1 by (1)(1) 6972.3 = (100 − p2) 6972.3 = (100 − p2) 68.9257 + p2 68.9257 + p2 70.9249 70.9249

6972.3 = 6892.57 − p2 6972.3 = 6892.57 − p2 68.9257 + p2 68.9257 + p2 70.9249 70.92496972.3 − 6892.57 = p2 6972.3 − 6892.57 = p2 (70.9249 − 68.9257) (70.9249 − 68.9257)

6972.3 − 6892.576972.3 − 6892.57p2 = ─────────── = 39.88% p1= 100 − p2 = 60.12% p2 = ─────────── = 39.88% p1= 100 − p2 = 60.12% 70.9249 − 68.925770.9249 − 68.9257

Atoms and the MoleAtoms and the Mole

A A collection termcollection term states states

a specific number of a specific number of

items.items.

• 1 dozen donuts 1 dozen donuts

= 12 donuts= 12 donuts

• 1 ream of paper 1 ream of paper

= 500 = 500 sheetssheets

• 1 case 1 case = 24 cans= 24 cans


A A molemole is (a collection number) the amount of a is (a collection number) the amount of a

substance that containssubstance that contains

• the same number of particles (atoms, the same number of particles (atoms, molecules, ions, protons, electrons, etc.) as molecules, ions, protons, electrons, etc.) as there are carbon atoms in 12 g of carbon-12 there are carbon atoms in 12 g of carbon-12 isotopeisotope

• 1 mol = 6.022 x 101 mol = 6.022 x 102323 particles particles (Avogadro’s (Avogadro’s number). Amadeo Avogadronumber). Amadeo Avogadro

• The number is referred to the atomic mass The number is referred to the atomic mass assignedassigned to carbon-12 isotope. to carbon-12 isotope.


1 mole of …1 mole of … Number of particlesNumber of particles

1 mole C 1 mole C = 6.022 x 10 = 6.022 x 102323 C atoms C atoms

1 mole Na 1 mole Na = 6.022 x 10 = 6.022 x 102323 Na atoms Na atoms

1 mole Au1 mole Au = 6.022 x 10 = 6.022 x 102323 Au atoms Au atoms

1 mole electrons = 6.022 x 101 mole electrons = 6.022 x 102323 electrons electrons

1 mole H1 mole H22OO = 6.022 x 10 = 6.022 x 102323 H H22O moleculesO molecules

1 mole Na1 mole Na++ = 6.022 x 10 = 6.022 x 102323 Na Na++ ions ions

Molar MassMolar MassThe The molar massmolar mass of any element is the mass in of any element is the mass in

grams of 6.022 x 10grams of 6.022 x 102323 atoms of that element, atoms of that element,

i.e., one i.e., one molemole of the element. of the element.

Molar massMolar mass is abbreviated is abbreviated MM, has units of , has units of

grams per mole grams per mole (g/mol),(g/mol), and is numerically and is numerically

equal to the atomic weight of the element equal to the atomic weight of the element ((periodic tableperiodic table))..

Molar mass of Na Molar mass of Na = 22.990 g/mol= 22.990 g/mol

Molar mass of Cl Molar mass of Cl = 35.453 g/mol= 35.453 g/mol

Molar mass of O Molar mass of O = 15.999 g/mol= 15.999 g/mol

Conversion factorsConversion factors Avogadro’s number Avogadro’s number 6.022 x 106.022 x 102323 can be written as can be written as

equalities and conversion factors.equalities and conversion factors.Equality:Equality:1 mole = 6.022 x 101 mole = 6.022 x 102323 particles = molar mass (g) particles = molar mass (g)Conversion Factors: particles = atoms or moleculesConversion Factors: particles = atoms or molecules6.022 x 106.022 x 102323 particles particles and and 1 mole 1 mole 1 mole1 mole 6.022 x 10 6.022 x 102323 particles particles

6.022 x 106.022 x 102323 particles particles and and molar mass (g) molar mass (g) molar mass (g) molar mass (g) 6.022 x 10 6.022 x 102323 particles particles

1 mole 1 mole and and molar mass (g) molar mass (g) molar mass (g) molar mass (g) 1 mole 1 mole

Converting moles Converting moles ↔↔ mass mass Moles to mass Mass to molesMoles to mass Mass to moles g 1 molg 1 molmoles moles x x ──────── = grams = grams gg x x ────= moles────= moles 1 mol grams 1 mol grams

The The molar massmolar mass as conversion factors as conversion factors

What is the mass of silicon represented by What is the mass of silicon represented by

0.250 moles of this element? 0.250 moles of this element? MM of Si = 28.086 of Si = 28.086 28.09 g g/mol 28.09 g g/mol

0.250 moles 0.250 moles x x ──────────── = 7.02 g Si = 7.02 g Si 1 mol1 mol

How many moles of manganese are 19.36 g ofHow many moles of manganese are 19.36 g of

that metal? that metal? MM of Mn = 54.938 g/mol of Mn = 54.938 g/mol 1 mol 1 mol 19.36 g 19.36 g x x ────────── = 0.352384 = = 0.352384 = 0.35240.3524 moles moles

54.938 g 4 SF54.938 g 4 SF

How many atoms of calcium are in 4.008 g ofHow many atoms of calcium are in 4.008 g of

that metal? that metal? MM of Ca = 40.08 g/mol of Ca = 40.08 g/mol

1 mol 6.022 x 101 mol 6.022 x 102323 atoms atoms 4.008 g 4.008 g x x ──────────── x x ────────────────────────── 40.08 g 1 mol40.08 g 1 mol

= 6.022 x 10= 6.022 x 102222 Ca atoms Ca atoms

The density of Au is 19.32 g/cmThe density of Au is 19.32 g/cm33. What is the . What is the volume of a piece of gold that contains 2.6 x 10volume of a piece of gold that contains 2.6 x 102424 atoms? If the piece of metal is a square with a atoms? If the piece of metal is a square with a thickness of 0.10 cm, what is the length (in cm) of thickness of 0.10 cm, what is the length (in cm) of one side of the square? one side of the square? AW = 196.97 g/molAW = 196.97 g/mol

196.97 g Au196.97 g Au2.6 x 102.6 x 102424 atoms Au atoms Au x x ──────────────────────── = 850 g Au = 850 g Au 6.022 x 106.022 x 102323 atoms atoms

1 cm1 cm33 850 g Au850 g Au x x ──────────────── = 44 cm = 44 cm33 Au Au 19.32 g Au19.32 g Au side = side = ll thickness (th)thickness (th)

V = th x A = th x V = th x A = th x ll22 A = area = A = area = ll22

l l = = SQRT SQRT (V/th) = (V/th) = SQRT SQRT (44 cm(44 cm33 / 0.10 cm) = 21 cm / 0.10 cm) = 21 cm

What is the average mass of one What is the average mass of one germanium atom? germanium atom? MM Ge = 72.59 g/mol Ge = 72.59 g/mol

Here we have to divide the mass of a Here we have to divide the mass of a mole by the number of atoms in that mole by the number of atoms in that mole.mole.

1 mole Ge = 72.59 g = 6.02 x 101 mole Ge = 72.59 g = 6.02 x 102323 atoms atoms

72.59 g Ge 1 mol Ge g Ge72.59 g Ge 1 mol Ge g Ge ─────── ─────── x x ────────────────────────── = 1.205 x10 = 1.205 x10-22-22 ────────── 1 mol Ge 6.022 x101 mol Ge 6.022 x102323 atoms Ge atom Ge atoms Ge atom Ge

0.0000000000000000000001205 g !!!!!!!0.0000000000000000000001205 g !!!!!!!

Periodic Table(*)Periodic Table(*)• a listing of the elements arranged according a listing of the elements arranged according

to their chemical and physical propertiesto their chemical and physical properties• elements are arranged according to similar elements are arranged according to similar

properties. properties. • Groups or families Groups or families contain elements with contain elements with

similar properties in vertical similar properties in vertical columnscolumns..

• periodsperiods are horizontal are horizontal rowsrows of elements. of elements. Every period has a number (row) from 1 Every period has a number (row) from 1 through 7.through 7.

(*) originally Mendeleev by (*) originally Mendeleev by atomic massatomic mass (1869), (1869), later Moseley by later Moseley by increasing atomic numberincreasing atomic number (1913).(1913).

Periodic TablePeriodic Table

• referred to by number or top elementreferred to by number or top element• some have names: some have names: The Representative ElementsThe Representative Elements• alkali metals - group 1Aalkali metals - group 1A• alkaline earth metals - group 2Aalkaline earth metals - group 2A• noble gases - group 8Anoble gases - group 8A• halogens - group 7Ahalogens - group 7A• chalcogens - group 6Achalcogens - group 6A• pnictogens - group 5Apnictogens - group 5A

GroupsGroups

Group 1A(1), the Group 1A(1), the alkali metalsalkali metals, includes , includes lithium, sodium, potassium, rubidium, lithium, sodium, potassium, rubidium, cesium, and franciumcesium, and francium

Alkali MetalsAlkali Metals

Group 7A(17) Group 7A(17) the the halogenshalogens, , includes includes fluorine, fluorine, chlorine, chlorine, bromine, and bromine, and iodine.iodine.

HalogensHalogens

Representative ElementsRepresentative Elements

1

Cr98

H

Li

Na

K

Rb

Cs

Fr

3

11

19

37

55

87

1.008

6.941

22.99

39.10

85.47

132.9

4

12

20

38

56

88

9.012

24.31

40.08

87.62

137.3

Be

Mg

Ca

Sr

Ba

Ra

21

39

57

89

44.96

88.91

138.9

Sc

Y

La

Ac

22

40

72

104

47.88

91.22

178.5

Ti

Zr

Hf

Unq

23

41

73

105

50.94

92.91

180.9

V

Nb

Ta

Unp

24

42

74

106

52.00

95.94

183.8

Mo

W

Unh

25

43

75

54.94

186.2

Mn

Tc

Re

Fe

Ru

Os

26

44

76

55.85

101.1

190.2

27 28 29 30

58.93 58.69 63.55 65.39Co Ni Cu Zn

Rh Pd Ag Cd

Ir Pt Au Hg

45 46 47 48

77 78 79 80102.9 106.4 107.9 112.4

192.2 195.1 200.6197.0

2

5 6 7 8 9 10

13 14 15 16 17 18

31 32 33 34 35 36

49 50 51 52 53 54

81 82 83 84 85 86

4.003

10.81 12.01 14.01 16.00 19.00 20.18

26.98 28.09 30.97 32.07 35.45 39.95

69.72 72.59 74.92 78.96 79.90 83.80

114.8 118.7 121.8 127.6 126.9 131.3

204.4 207.2 209.0

He

B C N O F Ne

Al Si P S Cl Ar

Ga Ge As Se Br Kr

In Sn Sb Te I Xe

Tl Pb Bi Po At Rn

Cr

11A

2A

3B 4B 5B 6B 7B 8B 1B 2B

3A 4A 5A 6A 7A

8A

58 59 60 61 62 63 64 65 66 67 68 69 70 71

90 91 92 93 94 95 96 97 98 99 100 101 102 103140.1 140.9 144.2 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 175.0

232.0 238.0

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Fm Md No LwTh Pa U Np Pu Am Cm Bk Cf Es

(223) (226) (227) (257) (260) (263)

(210) (210) (222)

(257)(254)(256)(253)(254)(249)(247)(243)(242)(237) (247)(231)

(147)

(98)

107 108 109Uns Uno Une(262) (265) (266)

1

2

3 4 5 6 7 8 9 10 11 12

13 14 15 16 17

18

8B8B

Transition ElementsTransition Elements

1

Cr98

H

Li

Na

K

Rb

Cs

Fr

3

11

19

37

55

87

1.008

6.941

22.99

39.10

85.47

132.9

4

12

20

38

56

88

9.012

24.31

40.08

87.62

137.3

Be

Mg

Ca

Sr

Ba

Ra

21

39

57

89

44.96

88.91

138.9

Sc

Y

La

Ac

22

40

72

104

47.88

91.22

178.5

Ti

Zr

Hf

Unq

23

41

73

105

50.94

92.91

180.9

V

Nb

Ta

Unp

24

42

74

106

52.00

95.94

183.8

Mo

W

Unh

25

43

75

54.94

186.2

Mn

Tc

Re

Fe

Ru

Os

26

44

76

55.85

101.1

190.2

27 28 29 30

58.93 58.69 63.55 65.39Co Ni Cu Zn

Rh Pd Ag Cd

Ir Pt Au Hg

45 46 47 48

77 78 79 80102.9 106.4 107.9 112.4

192.2 195.1 200.6197.0

2

5 6 7 8 9 10

13 14 15 16 17 18

31 32 33 34 35 36

49 50 51 52 53 54

81 82 83 84 85 86

4.003

10.81 12.01 14.01 16.00 19.00 20.18

26.98 28.09 30.97 32.07 35.45 39.95

69.72 72.59 74.92 78.96 79.90 83.80

114.8 118.7 121.8 127.6 126.9 131.3

204.4 207.2 209.0

He

B C N O F Ne

Al Si P S Cl Ar

Ga Ge As Se Br Kr

In Sn Sb Te I Xe

Tl Pb Bi Po At Rn

Cr

11A

2A

3B 4B 5B 6B 7B 8B 1B 2B

3A 4A 5A 6A 7A

8A

58 59 60 61 62 63 64 65 66 67 68 69 70 71

90 91 92 93 94 95 96 97 98 99 100 101 102 103140.1 140.9 144.2 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 175.0

232.0 238.0



(223) (226) (227) (257) (260) (263)

(210) (210) (222)

(257)(254)(256)(253)(254)(249)(247)(243)(242)(237) (247)(231)

(147)

(98)

107 108 109Uns Uno Une(262) (265) (266)

1

2

3 4 5 6 7 8 9 10 11 12

13 14 15 16 17

18

8B8B

Colors of solutions of Colors of solutions of Transition Metal CompoundsTransition Metal Compounds

Inner Transition ElementsInner Transition Elements

1

Cr98

H

Li

Na

K

Rb

Cs

Fr

3

11

19

37

55

87

1.008

6.941

22.99

39.10

85.47

132.9

4

12

20

38

56

88

9.012

24.31

40.08

87.62

137.3

Be

Mg

Ca

Sr

Ba

Ra

21

39

57

89

44.96

88.91

138.9

Sc

Y

La

Ac

22

40

72

104

47.88

91.22

178.5

Ti

Zr

Hf

Unq

23

41

73

105

50.94

92.91

180.9

V

Nb

Ta

Unp

24

42

74

106

52.00

95.94

183.8

Mo

W

Unh

25

43

75

54.94

186.2

Mn

Tc

Re

Fe

Ru

Os

26

44

76

55.85

101.1

190.2

27 28 29 30

58.93 58.69 63.55 65.39Co Ni Cu Zn

Rh Pd Ag Cd

Ir Pt Au Hg

45 46 47 48

77 78 79 80102.9 106.4 107.9 112.4

192.2 195.1 200.6197.0

2

5 6 7 8 9 10

13 14 15 16 17 18

31 32 33 34 35 36

49 50 51 52 53 54

81 82 83 84 85 86

4.003

10.81 12.01 14.01 16.00 19.00 20.18

26.98 28.09 30.97 32.07 35.45 39.95

69.72 72.59 74.92 78.96 79.90 83.80

114.8 118.7 121.8 127.6 126.9 131.3

204.4 207.2 209.0

He

B C N O F Ne

Al Si P S Cl Ar

Ga Ge As Se Br Kr

In Sn Sb Te I Xe

Tl Pb Bi Po At Rn

Cr

11A

2A

3B 4B 5B 6B 7B 8B 1B 2B

3A 4A 5A 6A 7A

8A

58 59 60 61 62 63 64 65 66 67 68 69 70 71

90 91 92 93 94 95 96 97 98 99 100 101 102 103140.1 140.9 144.2 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 175.0

232.0 238.0



(223) (226) (227) (257) (260) (263)

(210) (210) (222)

(257)(254)(256)(253)(254)(249)(247)(243)(242)(237) (247)(231)

(147)

(98)

107 108 109Uns Uno Une(262) (265) (266)

1

2

3 4 5 6 7 8 9 10 11 12

13 14 15 16 17

18

8B8B

• rows = periodsrows = periods

• gradual transition in gradual transition in properties from metallic to properties from metallic to nonmetallic moving from left nonmetallic moving from left to right across a periodto right across a period

MetalsMetals• Malleable: can be hammered or pressed Malleable: can be hammered or pressed

into new shapes (coins, rings, etc.)into new shapes (coins, rings, etc.)• Ductile: can be pressed, beaten, or drawn Ductile: can be pressed, beaten, or drawn

into shape when cold (wires, such as Cu)into shape when cold (wires, such as Cu)• solid at room temperature (except for Hg)solid at room temperature (except for Hg)• lusterluster• photoelectric effect (ephotoelectric effect (e–– emission due to emission due to

light)light)• thermionic effect (ethermionic effect (e–– emission due to heat) emission due to heat)• readily readily loselose electrons electrons• good thermal and electrical conductorsgood thermal and electrical conductors

NonmetalsNonmetals

• solid, liquid, or gassolid, liquid, or gas

• brittle if solid (fracture)brittle if solid (fracture)

• non-malleable, non-ductilenon-malleable, non-ductile

• thermal and electrical insulatorsthermal and electrical insulators

• do not exhibit photoelectric effectdo not exhibit photoelectric effect

• do not exhibit thermionic effectdo not exhibit thermionic effect

• readily readily gaingain electrons electrons

Metalloids (Semimetals)Metalloids (Semimetals)

• properties intermediate to those of properties intermediate to those of metals and nonmetalsmetals and nonmetals

• are located around the solid ladder are located around the solid ladder between metals and non-metals in between metals and non-metals in periodic tableperiodic table

• B, Si, Ge, As, Sb, Te, Po, AtB, Si, Ge, As, Sb, Te, Po, At

Noble gasesNoble gases

• Are the least reactive elementsAre the least reactive elements

• Are gases, none-abundant on Earth, Are gases, none-abundant on Earth, but He is the second in the universe but He is the second in the universe after hydrogen after hydrogen

• Neon in advertising signs Neon in advertising signs

• Some lasers are made of He, Ar, KrSome lasers are made of He, Ar, Kr

Learning CheckLearning Check

Identify each of the following elements as Identify each of the following elements as 1) metal 1) metal 2) nonmetal 3) metalloid 2) nonmetal 3) metalloid

A. sodiumA. sodium ________B. chlorineB. chlorine ________C. silicon C. silicon ________D. ironD. iron ________E. carbonE. carbon ________F. antimony ____F. antimony ____


Match the elements to the description.Match the elements to the description.

A. Metals in Group 4A(14) A. Metals in Group 4A(14) 1) Sn, Pb 2) C, Si 3) C, Si, Ge, Sn1) Sn, Pb 2) C, Si 3) C, Si, Ge, Sn

B. Nonmetals in Group 5A(15)B. Nonmetals in Group 5A(15) 1) As, Sb, Bi 1) As, Sb, Bi 2) N, P 2) N, P 3) N, P, As, Sb 3) N, P, As, Sb

C. Metalloids in Group 4A(14)C. Metalloids in Group 4A(14) 1) C, Si, Ge, 2) Si, Ge 3) Si, Ge, Sn, Pb1) C, Si, Ge, 2) Si, Ge 3) Si, Ge, Sn, Pb

Learning CheckLearning CheckThe elements magnesium and calcium are in what The elements magnesium and calcium are in what group? group? a. alkali metals b. alkaline earth metalsa. alkali metals b. alkaline earth metalsc. halogens d. noble gasesc. halogens d. noble gases

Which elements are nonmetals? Which elements are nonmetals? a. sodium and potassiuma. sodium and potassiumb. magnesium and bariumb. magnesium and bariumc. boron and aluminum d. carbon and brominec. boron and aluminum d. carbon and bromine

Identify the period number for the row that ends in Identify the period number for the row that ends in argon. argon. a. Period 1 b. Period 2 c. Period 3 d.Period 4a. Period 1 b. Period 2 c. Period 3 d.Period 4

Learning CheckLearning CheckWhich statement is characteristic of metals?Which statement is characteristic of metals?

A. They are shiny. A. They are shiny. B. They are poor conductors of electricity. B. They are poor conductors of electricity. C. They melt at high temperatures. C. They melt at high temperatures.

a. statement A only b. statements A and B only a. statement A only b. statements A and B only c. statements A, B, and Cc. statements A, B, and Cd. statements A and C onlyd. statements A and C only

Which statement is false?Which statement is false?

A. Potassium is an alkali metal. A. Potassium is an alkali metal. B. Strontium is an alkaline earth metal. B. Strontium is an alkaline earth metal. C. Argon is a noble gas. C. Argon is a noble gas. D. Zinc in a halogen. D. Zinc in a halogen.


What is the right order of increasing metallic What is the right order of increasing metallic

character for the elements Rb, F, P, Ga?character for the elements Rb, F, P, Ga?

Rb < F < P < GaRb < F < P < Ga

P < F < Rb < GaP < F < Rb < Ga

Ga< Rb < P < FGa< Rb < P < F

F < P < Ga < RbF < P < Ga < Rb

Learning CheckLearning CheckHow many atoms are in 1.50 mol Na?How many atoms are in 1.50 mol Na?

A.1.50 b. 9.03x10A.1.50 b. 9.03x102323 c. 3.00 d. 2.49x10 c. 3.00 d. 2.49x10-24-24 e. 345 e. 345

6.0226.02210102323 atoms atoms 1.50 mol 1.50 mol ──────────── = ──────────── = 9.03 x 109.03 x 102323 atoms atoms 1 mol1 mol

How many moles of Ar in 5.22 x 10How many moles of Ar in 5.22 x 102222 atoms of this atoms of this

noble gas? a. 11.5 b. 0.0867 c. 1.15x10noble gas? a. 11.5 b. 0.0867 c. 1.15x102222

d. 8.67x10d. 8.67x102323 e. 3.14 x e. 3.14 x10104646

1 mol1 mol 5.22 x 105.22 x 102222 atoms atoms ──────────── = 0.0867 mol──────────── = 0.0867 mol 6.0226.02210102323 atoms atoms


What is the mass (grams) of one atom of Na?What is the mass (grams) of one atom of Na?

a. 22.99 b. 0.04350 c. 3.818 x 10a. 22.99 b. 0.04350 c. 3.818 x 10 2323 b. 2.619x10 b. 2.619x102222

22.99 g22.99 g1 mol Na 1 mol Na ─────────── = ─────────── = 3.818 x 103.818 x 102323 g/atomg/atom 6.0226.02210102323 atoms atoms

chapter 2 atoms and elements. dalton’s atomic theory ( beginning of 19 th century ) all matter is...

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