Unit 4: The Periodic Tableand Periodicity

Chemistry

The Origin of Elements

elements known to the ancients…

Element names come from a variety of sources

place names…

famous people…

foreign languages…

mythology-related names…

names related to element properties…

S, Cu, C, Sn,

Fr, Po, Ge, Ga, Eu, Am, Cf, Sc

Es, Fm, Md, No, Lr, Rf, Bh,

Sb, Rb,

Ta, Ti, Pd Pm, Th,

W, Fe, Au, Ag, Pb, Sn, Ni

Ro?

Au

Ir

atomic number

Background on the Periodic Table

Dmitri Mendeleev: given creditfor Periodic Table (~1870)

--

--

organized Table byincreasing atomic mass left spaces and predictedproperties of undiscoveredelements

Henry Moseley: put elements inorder of increasing____________.

Mendeleev

Moseley

Mendeleev’s Early Periodic Table

GRUPPE I GRUPPE II GRUPPE III GRUPPE IV GRUPPE V GRUPPE VI GRUPPE VII GRUPPE VIII ___ ___ ___ ___

RH4 RH3 RH2 RH R2O RO R2O3 RO2 R2O5 RO3 R2O7 RO4 R

EIH

EN

1

2

3

4

5

6

7

8

9

10

11

12

From Annalen der Chemie und Pharmacie, VIII, Supplementary Volume for 1872, p. 151.

H = 1

Li = 7 Be = 9.4 B = 11 C = 12 N = 14 O = 16 F = 19

Na = 23 Mg = 24 Al = 27.3 Si = 28 P = 31 S = 32 Cl = 35.5

K = 39 Ca = 40 __ = 44 Ti = 48 V = 51 Cr = 52 Mn = 55 Fe = 56, Co = 59, Ni = 59, Cu = 63(Cu = 63) Zn = 65 __ = 68 __ = 72 As = 75 Se = 78 Br = 80

Rb = 85 Sr = 87 ? Yt = 88 Zr = 90 Nb = 94 Mo = 96 __ = 100 Ru = 104, Rh = 104, Pd = 106, Ag = 108 (Ag = 108) Cd = 112 In = 113 Sn = 118 Sb = 122 Te = 125 J = 127

Cs = 133 Ba = 137 ? Di = 138 ? Ce = 140 __ __ __ __ __ __ __

( __ ) __ __ __ __ __ __

__ __ ? Er = 178 ? La = 180 Ta = 182 W = 184 __ Os = 195, Ir = 197, Pt = 198, Au = 199 (Au = 199) Hg = 200 Tl= 204 Pb = 207 Bi = 208 __ __

__ __ __ Th = 231 __ U = 240 __ __ __ __ __

TABELLE II

?? ?

Elements Properties are PredictedProperty Mendeleev’s Predictions in 1871 Observed Properties

Molar Mass Oxide formula Density of oxide Solubility of oxide

Scandium (Discovered in 1877)44 gM2O3

3.5 g / mlDissolves in acids

43.7 gSc2O3

3.86 g / mlDissolves in acids

Molar mass Density of metal Melting temperature Oxide formula Solubility of oxide

Gallium (Discovered in 1875)68 g

6.0 g / mlLowM2O3

Dissolves in ammonia solution

69.4 g5.96 g / ml

30 0CGa2O3

Dissolves in ammonia

Molar mass Density of metal Color of metal Melting temperature Oxide formula Density of oxide Chloride formula Density of chloride Boiling temperature of chloride

Germanium (Discovered in 1886)72 g

5.5 g / mlDark gray

HighMO2

4.7 g / mlMCl4

1.9 g / mlBelow 100 oC

71.9 g5.47 g / ml

Grayish, white900 0CGeO2

4.70 g / mlGeCl4

1.89 g / ml86 0C

O’Connor Davis, MacNab, McClellan, CHEMISTRY Experiments and Principles 1982, page 119,

P

Zn As

Sb

Pt Bi

Midd. -1700

Cr Mn

Li

K

N O F

Na

BBe

H

Al Si Cl

Ca Ti V Co Ni Se Br

Sr Y Zr Nb Mo Rh Pd Cd Te I

Ba Ta W Os Ir

Mg

Ce Tb Er

Th U

1735-1843

Discovering the Periodic Table

C

S

Fe Cu

Ag Sn

Au Hg Pb

Ancient Times

He

Sc Ga Ge

Rb Ru In

Cs Tl

Pr Nd Sm Gd Dy Ho Tm Yb

La

1843-1886 Ne

Ar

Kr

Xe

Po Rn

Ra

Eu Lu

Pa

Ac

1894-1918

Tc

Hf Re At

Fr

Pm

Np Pu Am Cm Bk Cf Es Fm Md No Lr

1923-1961

Rf Db Sg Bh Hs Mt

1965-

Journal of Chemical Education, Sept. 1989

Ds Rg Cn Uut Fl Uup

1965-

Lv Uus Uuo

1965-

Describing the Periodic Table

periodic law: the properties of elements repeat every so often

period: group (family):

horizontal row; there are 7vertical column; there are 18

181716151413

129 10 1187654

1

3

21234

67

5

Dutch Periodic Table

106107

108

109

110

111

112

113

114

115116

117 118

Strong, Journal of Chemical Education, Sept. 1989, page 743

How to Organize Elements… Periodic Table Designs

Regions of the Tablemetals: left side of Table; form cationsproperties:

lustrous(shiny)

ductile(can pullinto wire)

malleable(can hammerinto shape)

good conductors(heat and electricity)

nonmetals: right side of Table; form anions

properties: good insulatorsgases or brittle solids

Regions of the Table (cont.)

Br2I2S8Nebromineiodinesulfurneon

computer chips

metalloids (semimetals): “stair” between metalsand nonmetals

properties: in-between those of metalsand nonmetals; “semiconductors”

Regions of the Table (cont.)

(B, Si, Ge, As, Sb, Te, Po)

Si and Ge

computer chips

metals

nonmetals

alkali metals:

alkaline earth metals:

halogens:

noble gases:

contain f orbitals

lanthanides:

coinage metals:

transition elements:

main block (representative) elements:

group 1 (except H); 1+ charge;very reactive

group 2; 2+ charge;less reactive than

alkalisgroup 17; 1– charge; very reactive

group 18; no charge; unreactive

elements 58–71actinides: elements 90–103

group 11

groups 3–12; variable charges

groups 1, 2, 13–18

alkaline earth metalshalogens

noble gaseslanthanides

alkali metals actinidescoinage metalstransition elements

main block elementsmetalloids

hydrogenmore nonmetals

more metals

Same number of valence e– =

Li Na In any group, the element BELOW has one more

occupied energy level than does the element ABOVE.

Li Na

similar properties

1s2 2s1 1s2 2s2 2p6 3s1

The period that an element is in, is the same as theenergy level that its valence electrons are in.Li Na

v.e– in 2nd E.L. v.e– in 3rd E.L.

in 3rd periodin 2nd period

Periodicity

there are trends in properties of elements

-- left-right AND up-down trends atomic radius: the size of a neutral atom

add a new energylevel each time

WHY?…increases as we go

…decreases as we go WHY?

coulombic attraction: attraction between (+) and (–)

it has to do with…

Coulombic attraction depends on…

2– 2+

2+ 2–

2–

1+

2+

amount of charge distance between charges

1–

H

He

+ –As we go ,

more coulombic attraction, no new energy level, more pull, smaller size

+ –

+ + – –

Atomic Radii of Representative Elements (nm)

LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World , 1996, page 175

Li

Na

K

Rb

Cs

ClSPSiAl

BrSeAsGeGa

ITeSbSnIn

Tl Pb Bi

Mg

Ca

Sr

Ba

Be FONCB

0.152 0.111

0.186 0.160

0.231 0.197

0.244 0.215

0.262 0.217

0.088 0.077 0.070 0.066 0.064

0.143 0.117 0.110 0.104 0.099

0.122 0.122 0.121 0.117 0.114

0.162 0.140 0.141 0.137 0.133

0.171 0.175 0.146 0.140 0.140

1A 2A 3A 4A 5A 6A 7A

AtPo

shielding effect: kernel e– “shield” valence e–

from attractive force of the nucleus

Li v.e–

K v.e–

-- caused by kernel and valence e–

repelling each other

As we go , shielding effect increases

tougher to remove

easierto remove

ionic radius:

cations anions

Ca atom Ca2+ ion Cl atom Cl– ion

the size of an ion

20 p+ 20 e–

20 p+ 18 e–

17 p+ 17 e–

17 p+ 18 e–

Ca Ca2+ Cl Cl–

cations are smaller anions are larger

Atomic Radii

Li

Na

K

Rb

Cs

ClSPSiAl

BrSeAsGeGa

ITeSbSnIn

Tl Pb Bi

Mg

Ca

Sr

Ba

Be FONCB1.52 1.11

1.86 1.60

2.31 1.97

2.44 2.15

2.62 2.17

0.88 0.77 0.70 0.66 0.64

1.43 1.17 1.10 1.04 0.99

1.22 1.22 1.21 1.17 1.14

1.62 1.40 1.41 1.37 1.33

1.71 1.75 1.46

IA IIA IIIA IVA VA VIA VIIA

= 1 Angstrom

0.60 0.31

0.95 0.65

1.33 0.99

1.48 1.13

1.69 1.35

1.71 1.40 1.36

0.50 1.84 1.81

0.62 1.98 1.85

0.81 2.21 2.16

0.95

IA IIA IIIA IVA VA VIA VIIA

= 1 Angstromor 10-10 m

Li1+ Be2+

Na1+ Mg2+

Ba2+

Sr2+

Ca2+K1+

Rb1+

Cs1+

Cl1-

N3- O2- F1-

S2-

Se2- Br1-

Te2- I1-

Al3+

Ga3+

In3+

Tl3+

Ionic Radii

ionization energy: the energy required to remove an e– from an atom

M + 1st I.E.

M+ + 2nd I.E.

M2+ + 3rd I.E.

As we go , 1st I.E….

As we go , 1st I.E….

M+ + e–

M2+ + e–

M3+ + e–

removes 1st e–

Each successive ionization requiresmore energy than the previous one.

decreases.

increases.

(due to the shielding effect)

*M = metal

Ionization Energies (kJ/mol)

Element

Na

Mg

Al

Si

P

S

Cl

ArHerron, Frank, Sarquis, Sarquis, Cchrader, Kulka, Chemistry 1996, Heath, page

1st

498

736

577

787

1063

1000

1255

1519

2nd

4560

1445

1815

1575

1890

2260

2295

2665

3rd

6910

7730

2740

3220

2905

3375

3850

3945

4th

9540

10,600

11,600

4350

4950

4565

5160

5770

5th

13,400

13,600

15,000

16,100

6270

6950

6560

7320

6th

16,600

18,000

18,310

19,800

21,200

8490

9360

8780Shaded area on table denotes core electrons.

H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca0

2

4

6

8

10

12

14

16

Ionization Energies of the First 20 Elements

1st IE2nd IE3rd IE

Element

Ener

gy ((

kJ/m

ol x

10–

3)

electronegativity:

Linus Pauling quantifiedthe electronegativity scale

the tendency fora bonded atom toattract e– to itself

As we go , electronegativity…

As we go , electronegativity…

decreases

increases

electronegativity increases Fluorine is the most electro-negative element

1

2

3

4

5

6

1

2

3

4

5

6

Electronegativities

7

Be

1.5

Al

1.5

Si

1.8

Ti

1.5

V

1.6

Cr

1.6

Mn

1.5

Fe

1.8

Co

1.8

Ni

1.8

Cu

1.9

Zn

1.7

Ga

1.6

Ge

1.8

Nb

1.6

Mo

1.8

Tc

1.9

Ag

1.9

Cd

1.7

In

1.7

Sn

1.8

Sb

1.9

Ta

1.5

W

1.7

Re

1.9

Hg

1.9

Tl

1.8

Pb

1.8

Bi

1.9

1.5 - 1.9

N

3.0

O

3.5

F

4.0

Cl

3.0

3.0 - 4.0

C

2.5

S

2.5

Br

2.8

I

2.5

2.5 - 2.9

Na

0.9

K

0.8

Rb

0.8

Cs

0.7

Ba

0.9

Fr

0.7

Ra

0.9

Below 1.0

H

2.1

B

2.0

P

2.1

As

2.0

Se

2.4

Ru

2.2

Rh

2.2

Pd

2.2

Te

2.1

Os

2.2

Ir

2.2

Pt

2.2

Au

2.4

Po

2.0

At

2.2

2.0 - 2.4

Per

iod

Actinides: 1.3 - 1.5

Li

1.0

Ca

1.0

Sc

1.3

Sr

1.0

Y

1.2

Zr

1.4

Hf

1.3

Mg

1.2

La

1.1

Ac

1.1

1.0 - 1.4

Lanthanides: 1.1 - 1.3

*

*y

y

1A

2A

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

3A 4A 5A 6A 7A

8A

Hill, Petrucci, General Chemistry An Integrated Approach 2nd Edition, page 373

8B