Chemistry 120 Chemical Composition of the World: Atoms 101 “indivisible, uncuttable” All matter is composed of atoms which cannot be further split

Chemistry 120

Chemical Composition of the World: Atoms 101

“indivisible, uncuttable”All matter is composed of atoms which cannot be further split into smaller portionsAtoms are completely solidAtoms are homogeneous, with no internal structureBetween atoms there is empty spaceAtoms differ in size

Democritus (c.460-c.370 B.C.)

Atoms, Molecules and Ions

Chemistry 120

John Dalton (1766-1844)



Chemistry 120


Thomson’s“blueberry muffin” modelElectrons embedded in a shell of positive charge

Rutherford’s modelElectrons randomly circulating around nucleus made of protons


Chemistry 120


The Modern Atom

Most of the atom is empty space.

Atomic radius = ~ 10-10 m

Nuclear radius = ~ 10-15 m

Volume ratio:

VAtom: VNucleus = ~ 1015

Au foil

Chemistry 120


The Modern Atom

The atom is made up of three fundamental particles

The proton, p+

The neutron, n0

The electron, e-

Most of the mass of the atom is contained in the nucleus

Nucleus

}Nuclear

Chemistry 120


The Modern Atom

proton neutron electron

Mass/kg 1.67x10-27 1.675x10-27 9.1x10-31

Charge* +1 0 -1

Location Nucleus Nucleus Atom

Stability Stable Unstable Stableoutside the nucleus

* In units of 1.6 x 10-19 C

Chemistry 120


The Modern Atom - Structure

A Small Dense Nucleus

Nuclear Radius: ~ 10-15 m (1 fm)

Density of the nucleus:

~ 100,000,000,000,000 gcm-3

Density of water = 1 gcm-3

The mass of the electron is ~ 1/2000 that of the proton and neutron – most of the mass of the atom is in the nucleus

Chemistry 120


The Four Forces of Nature

There are only four fundamental forces found in Nature.

Two are macroscopic

- gravity

- electromagnetism

Two are microscopic

- strong nuclear force

- weak nuclear force

Chemistry 120


The Four Forces of Nature

Two are very weak and are not important for the structure of the atom

- gravity

- weak nuclear force

Two bind the atom together

- strong nuclear force

- electromagnetism

Chemistry 120



Structure of the nucleus not well understood:

Particles all interact with each other

Chemistry 120





Internal constituents of the protons and neutrons interact

Chemistry 120






Nuclear force, the strong nuclear force, not well understood

Chemistry 120





Nuclear force, the strong nuclear force, not well understood

Very high energies needed for study


Chemistry 120



Structure of the atom is well understood:

Electrons flow around the nucleus

Chemistry 120





Bound to the central positive nucleus by the electromagnetic force:

Chemistry 120






Opposite Charges Attract

Chemistry 120






Opposite Charges Attract

Experimentally easy energies needed for study

Chemistry 120

Chemistry and the Modern Atom

Atoms bind together using their electrons

Chemistry is based in the physics of electrons in atoms

We understand electrons in atoms well enough to understand chemistry at a high level


Chemistry 120

The Chemical Atom

Atoms are neutral – they have no electrical charge

There are equal numbers of protons in the nucleus and electrons in the atom.

The charges on the electron and the proton are equal.


Chemistry 120

The Chemical Atom

Atomic numbers and mass numbers

The chemistry of each element is determined by the number and energy of the outer valence electrons.

The atom is neutral and so the number of protons equals the number of electrons.

The Atomic Number, Z, shows number of protons in the nucleus.


Chemistry 120

The Chemical Atom

The order of the elements in the periodic table is in the order of increasing number of protons in the nucleus and therefore electrons in the atom.

The mass number is the atomic mass and we write an element as

where X is the chemical symbol, A is the mass number and Z is the atomic number.


AZ X

42He

Chemistry 120

For Helium, He,

Mass = 4

Atomic number = 2


42He}

Chemistry 120

Isotopes

The number of protons determines the chemical identity of the element.

The number of neutrons in the nucleus does not affect the number of electrons and therefore the chemical identity.

Atoms which have different numbers of neutrons and the same number of protons are called

Isotopes


Chemistry 120

The mass of an atom A is given by

A = Z + N

Number of protons Number of neutrons

Isotopes have different masses but are chemically identical

58Ni 68.27 16O 99.762 60Ni 26.1 17O 0.03861Ni 1.13 18O 0.2 62Ni 3.59 64Ni 0.91


Chemistry 120

To calculate the natural mass of the element, multiply the abundance of the isotope by the mass of the isotope and add:

58Ni 68.27 60Ni 26.161Ni 1.1362Ni 3.59 64Ni 0.91


Chemistry 120


58Ni 68.27% 58 x 68.27/100 =60Ni 26.1% 60 x 26.1/100 =61Ni 1.13% 61 x 1.13/100 = 62Ni 3.59% 62 x 3.59/100 =64Ni 0.91% 64 x 0.91/100 =


Chemistry 120


58Ni 68.27% 58 x 68.27/100 = 39.596660Ni 26.1% 60 x 26.1/100 = 15.6661Ni 1.13% 61 x 1.13/100 = 0.689362Ni 3.59% 62 x 3.59/100 = 2.225864Ni 0.91% 64 x 0.91/100 = 0.5824


Chemistry 120


58Ni 68.27% 58 x 68.27/100 = 39.596660Ni 26.1% 60 x 26.1/100 = 15.6661Ni 1.13% 61 x 1.13/100 = 0.689362Ni 3.59% 62 x 3.59/100 = 2.225864Ni 0.91% 64 x 0.91/100 = 0.5824

58.7541


Chemistry 120

The Periodic Table

The Periodic Table is an ordered array of the elements, with rising atomic number.

First written down by Dimitri

Mendeléev as a list of the

elements with increasing atomic

Mass. The elements naturally

grouped themselves by chemical

properties.


Dimitri Mendeléev

(1834 – 1907)

Chemistry 120

s block p block1 H

1He2


Building the Periodic Table

Chemistry 120


Building the Periodic Tables block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

Al13

Si14

P15

S16

Cl17

Ar18


Building the Periodic Table

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36


The Periodic Table

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54


The Periodic Table

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

f blockLa57

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70


The Periodic Table

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

7 Fr86

Ra88

Lr103

Rf104

Db105

Sg106

Bh107

Hs108

Mt109

110 111 112

f blockLa57

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70

Ac89

Th90

Pa91

U92

Np93

Pu94

Am95

Cm96

Bk97

Cf98

Es99

Fm100

Md101

No102


The Periodic Table

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

7 Fr86

Ra88

Lr103

Rf104

Db105

Sg106

Bh107

Hs108

Mt109

110 111 112

f blockLa57

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70

Ac89

Th90

Pa91

U92

Np93

Pu94

Am95

Cm96

Bk97

Cf98

Es99

Fm100

Md101

No102


The S block

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

7 Fr86

Ra88

Lr103

Rf104

Db105

Sg106

Bh107

Hs108

Mt109

110 111 112

f blockLa57

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70

Ac89

Th90

Pa91

U92

Np93

Pu94

Am95

Cm96

Bk97

Cf98

Es99

Fm100

Md101

No102


The S block and P block

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

7 Fr86

Ra88

Lr103

Rf104

Db105

Sg106

Bh107

Hs108

Mt109

110 111 112

f blockLa57

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70

Ac89

Th90

Pa91

U92

Np93

Pu94

Am95

Cm96

Bk97

Cf98

Es99

Fm100

Md101

No102


The S block , P block

and D block

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

7 Fr86

Ra88

Lr103

Rf104

Db105

Sg106

Bh107

Hs108

Mt109

110 111 112

f blockLa57

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70

Ac89

Th90

Pa91

U92

Np93

Pu94

Am95

Cm96

Bk97

Cf98

Es99

Fm100

Md101

No102


The S block , P block ,

D block and F block

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

7 Fr86

Ra88

Lr103

Rf104

Db105

Sg106

Bh107

Hs108

Mt109

110 111 112

f blockLa57

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70

Ac89

Th90

Pa91

U92

Np93

Pu94

Am95

Cm96

Bk97

Cf98

Es99

Fm100

Md101

No102


The Radioactive elements

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

7 Fr86

Ra88

Lr103

Rf104

Db105

Sg106

Bh107

Hs108

Mt109

110 111 112

f blockLa57

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70

Ac89

Th90

Pa91

U92

Np93

Pu94

Am95

Cm96

Bk97

Cf98

Es99

Fm100

Md101

No102


Gases at room temperature

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

7 Fr86

Ra88

Lr103

Rf104

Db105

Sg106

Bh107

Hs108

Mt109

110 111 112

f blockLa57

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70

Ac89

Th90

Pa91

U92

Np93

Pu94

Am95

Cm96

Bk97

Cf98

Es99

Fm100

Md101

No102


Gases and liquids at room temperature

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

7 Fr86

Ra88

Lr103

Rf104

Db105

Sg106

Bh107

Hs108

Mt109

110 111 112

f blockLa57

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70

Ac89

Th90

Pa91

U92

Np93

Pu94

Am95

Cm96

Bk97

Cf98

Es99

Fm100

Md101

No102


The Non-metals

Chemistry 120

General Characteristics of Non-metals

Bad conductors of electricity

- often insulators or semiconductors

- conductivity rises with increasing temperature

Bad conductors of heat

Brittle, not maleable, not ductile


Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

7 Fr86

Ra88

Lr103

Rf104

Db105

Sg106

Bh107

Hs108

Mt109

110 111 112

f blockLa57

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70

Ac89

Th90

Pa91

U92

Np93

Pu94

Am95

Cm96

Bk97

Cf98

Es99

Fm100

Md101

No102


The Non-metals and

The Metals

Chemistry 120

General Characteristics of Metals

Good or excellent conductors of electricity

- conductivity falls with increasing temperature

- are often superconductors at low temperature

Good conductors of heat

Often maleable and ductile

- d block metals in general better than p block metals


Chemistry 120

Dalton and Compound Atoms


John Dalton rejuvenated the atomic theory and used the terms compound atoms and atoms to define the basic building blocks of matter.

Dalton’s compound atoms are today’s

MOLECULES

Chemistry 120

Molecules


A molecule is a compound where two or more atoms are bound together by sharing the outer electrons in a covalent bond.

Most molecular species are formed by the non-metals

Chemistry 120

Molecules


A molecule is a compound where two or more atoms are bound together by sharing the outer electrons in a covalent bond.

Most molecular species are formed by the non-metals

B5

C6

N7

O8

F9

Si14

P15

S16

Cl17

Ge32

As33

Se34

Br35

Sb51

Te52

I53

Xe54

Chemistry 120

Elements whose natural forms occur as molecules include


B5

C6

N7

O8

F9

Si14

P15

S16

Cl17

Ge32

As33

Se34

Br35

Sb51

Te52

I53

Xe54

Chemistry 120



B5

C6

N7

O8

F9

Si14

P15

S16

Cl17

Ge32

As33

Se34

Br35

Sb51

Te52

I53

Xe54

Nitrogen N2

Chemistry 120



B5

C6

N7

O8

F9

Si14

P15

S16

Cl17

Ge32

As33

Se34

Br35

Sb51

Te52

I53

Xe54

Nitrogen N2

Phosphorous P4

Chemistry 120



B5

C6

N7

O8

F9

Si14

P15

S16

Cl17

Ge32

As33

Se34

Br35

Sb51

Te52

I53

Xe54

Nitrogen N2

Phosphorous P4

Arsenic As4

Chemistry 120



B5

C6

N7

O8

F9

Si14

P15

S16

Cl17

Ge32

As33

Se34

Br35

Sb51

Te52

I53

Xe54

Nitrogen N2

Phosphorous P4

Arsenic As4Oxygen O2

Chemistry 120



B5

C6

N7

O8

F9

Si14

P15

S16

Cl17

Ge32

As33

Se34

Br35

Sb51

Te52

I53

Xe54

Nitrogen N2

Phosphorous P4


Sulfur S8

Chemistry 120



B5

C6

N7

O8

F9

Si14

P15

S16

Cl17

Ge32

As33

Se34

Br35

Sb51

Te52

I53

Xe54

Nitrogen N2

Phosphorous P4


Sulfur S8

Fluorine F2

Chemistry 120



B5

C6

N7

O8

F9

Si14

P15

S16

Cl17

Ge32

As33

Se34

Br35

Sb51

Te52

I53

Xe54

Nitrogen N2

Phosphorous P4


Sulfur S8

Fluorine F2

Chlorine Cl2

Chemistry 120



B5

C6

N7

O8

F9

Si14

P15

S16

Cl17

Ge32

As33

Se34

Br35

Sb51

Te52

I53

Xe54

Nitrogen N2

Phosphorous P4


Sulfur S8

Fluorine F2

Chlorine Cl2

Bromine Br2

Chemistry 120



B5

C6

N7

O8

F9

Si14

P15

S16

Cl17

Ge32

As33

Se34

Br35

Sb51

Te52

I53

Xe54

Nitrogen N2

Phosphorous P4


Sulfur S8

Fluorine F2

Chlorine Cl2

Bromine Br2

Iodine I2

Chemistry 120

As a molecule is a compound, it has a definite chemical composition and we write a formula for the composition:

Elemental sulfur has the formula

S8


Chemistry 120

As a molecule is a compound, it has a definite chemical composition and we write a formula for the composition:

Elemental sulfur has the formula

S8


Chemical Symbol

Number of atoms in the molecule

Chemistry 120

Methane CH4

Ethanol C2H6O

Sulfuric Acid H2SO4


Chemistry 120

Methane CH4 1 Carbon

4 Hydrogens

Ethanol C2H6O 2 Carbons

4 Hydrogens

1 Oxygen

Sulfuric Acid H2SO4 2 Hydrogens

1 Sulfur

4 Oxygens


Chemistry 120

There are several types of formulæ (not formulas)

Empirical formula: The simplest ratio of atoms

Molecular formula: The actual number of atoms in the molecule

Structural formula: The structure and number of atoms in the molecule


Chemistry 120

Empirical formula:

Acetic Acid: CH2O

Glucose CH2O

Formaldehyde CH2O


Chemistry 120

Empirical formula Molecular

Acetic Acid: CH2O C2H4O2

Glucose CH2O C6H12O6

Formaldehyde CH2O CH2O


Chemistry 120

Empirical formula Molecular Structural

Acetic Acid: CH2O C2H4O2

Glucose CH2O C6H12O6

Formaldehyde CH2O CH2O


H C

H

C

H

O

O H

OHC C

OH

H

C

H

HO

C

OH

H

C

OH

H

CH2OH

C

O

H H

Chemistry 120

Molecules with the same molecular formula but different structural formulæ are called

ISOMERS


Chemistry 120


ISOMERS

For C2H6O


Chemistry 120


ISOMERS

For C2H6O


H C

H

C

H

H

O

H

H

Ethanol

Chemistry 120


ISOMERS

For C2H6O


H C

H

C

H

H

O

H

H

Ethanol

or

Chemistry 120


ISOMERS

For C2H6O


H C

H

C

H

H

O

H

H

Ethanol

or H C

H

H

C

H

O

H

H

Dimethyl ether

Chemistry 120

Formulæ tell us

the simplest composition of the molecule

empirical formulæ

Or

the actual composition of the molecule

molecular formulæ

Or

the structure and composition of the molecule

structural formulæ


Chemistry 120

But the three dimensional structure of the

molecule is best represented using models or a

chemical drawing package (e.g. ChemDraw) as the

reactivity and chemistry of a molecule takes place

in three dimensions


Chemistry 120

http://www.sci.ouc.bc.ca/chem/molecule/molecule.html

Capsaicin

CaffeineStrychnine

RDX

Chemistry 120

Writing Formulæ

Prefixes denote the number of atoms

Mono 1 Hexa 6

Di 2 Hepta 7

Tri 3 Octa 8

Tetra 4 Nona 9

Penta 5 Deca 10


Chemistry 120

Writing Formulæ

The first element in the name is the one

farthest to the left

and

lowest in the group

Hydrogen and oxygen are sometimes exceptions


Chemistry 120

Writing Formulæ

The second name drops the suffix and adds

-ide

instead

chlorine chloride oxygen oxide


Chemistry 120

Example

1 phosphorous atoms 5 fluorine atoms


Chemistry 120

Example


Phosphorous


Chemistry 120

Example


Phosphorous Pentafluor


Chemistry 120

Example


Phosphorous Pentafluoride


PF5

Chemistry 120

Example S2F10


Chemistry 120

Example S2F10

2 sulfur atoms

- disulfur


Chemistry 120

Example S2F10

2 sulfur atoms

- disulfur

10 fluorine atoms

- decafluoride


Chemistry 120

Example S2F10

2 sulfur atoms

- disulfur

10 fluorine atoms

- decafluoride

disulfur decafluoride


Chemistry 120

Substances that are made up of molecules tend to be

mechanically soft

low melting and boiling

electrical insulators in solution and in the solid state


Chemistry 120

Atoms are neutral

equal numbers of protons (in the nucleus) and electrons (outside the nucleus)

charge on the electron and proton is equal

An atom that gains or loses one or more electrons is called an

ION


Chemistry 120

An atom that loses one or more electrons is positively charged and is called a

CATION

An atom that gains one or more electrons is negatively charged and is called an

ANION

PROTONS ARE NOT TRANSFERRED FROM THE NUCLEUS!!!


Chemistry 120

Compounds which are made up of ions are called

IONIC

In general they are

hard

brittle

insulators in the solid state but conductors in solution or in the melt

have high melting points and boiling points


Chemistry 120

Ionic compounds are held together by electrostatic forces between the ions – they are crystalline and there is no ‘minimum unit’ analogous to a molecule

Which element – which ion?

This depends on the electronic structure of the atom but in the s and p block.......


Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86


Monocations: Li+, Na+, K+, Rb+, Cs+

Monocations

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86



Dications: Be2+, Mg2+, Ca2+, Sr2+, Ba2+, Sn2+, Pb2+

Mono- and dications

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86



Dications: Be2+, Mg2+, Ca2+, Sr2+, Ba2+, Sn2+, Pb2+

Trications: Al3+, Ga3+

Mono-, di- and trications

Chemistry 120

s block p block1 H

1He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86


Chemistry 120

1 H1

He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86


Trications: Al3+, Ga3+

Mono-, di- and trications


Dications: Be2+, Mg2+, Ca2+, Sr2+, Ba2+

Sn2+, Pb2+

Trianions N3-, P3-

Dianions

O2-, S2-

Monoanions

Chemistry 120


Transition metals can from ions with more than one charge. Common ones include

Ti Ti3+ Ti4+ Co Co2+ Co3+

V V3+ V4+ V5+ Ni Ni2+

Mn Mn2+ Mn4+ Mn5+Cu Cu+ Cu2+

Fe Fe2+ Fe3+

Chemistry 120


These cations and anions are formed from atoms but we can form anions and cations from molecules. These are termed

POLYATOMIC IONS

1 H1

He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

3 Na11

Mg12

d block Al13

Si14

P15

S16

Cl17

Ar18

4 K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

5 Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

6 Cs55

Ba56

Lu71

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

Chemistry 120


Polyatomic Ions

These species exists as anions and cations and contain several atoms bound together in the same way as a molecule – covalently – but with one or more positive or or negative charge.

O

S

OOO

O N

O

O

S

O OO

O

P

OOO

2

23

H

N

HHH

O

HHH

C

C

C CC

CC

H

H

H

HH

H

H

S

H3C CH3

CH3

Chemistry 120


Acids, bases and salts

Svante Arrhenius defined

an acid is a compound which dissolves

in water or reacts with water to give

hydronium ions, H3O+(aq)

a base is a compound which dissolves

in water or reacts with water to give

hydroxide ions, OH- (aq)

Svante Arrhenius

(1859 – 1927)

Chemistry 120



Acidic and basic solutions are formed by dissolution or by reaction.

Dissolution

- a compound containing hydronium ions, H3O+

(aq) or hydroxide ions, OH- (aq) dissociates and gives an acidic or basic solution

Reaction

- a compound reacts with water to form an acidic or basic solution

Chemistry 120



For an acid A, the reaction is

For a acid B, the reactions are

AH + H2O(l) A-(aq) + H3O+

(aq)

BOH(s)+ H2O(l) B+(aq) + OH-

(aq)

B + H2O(l) BH+(aq) + OH-

(aq)

Chemistry 120



An example of the formation of an acid solution is

HBr(g) + H2O(l) Br-(aq)

+ H3O+(aq)

Chemistry 120



+ H3O+(aq)

Water Hydronium

ion


Water is protonated to form the hydronium ion – hydrogen bromide is a proton donor

Chemistry 120



+ H3O+(aq)

Hydrogen Bromide

Water

Bromide

Hydronium

ion


And the counter ion, necessary for electroneutrality is bromide ion.

Chemistry 120



An example of the formation of a basic solution by dissolution is

NaOH dissolves in water to give sodium ions and hydroxide ions. NaOH is an ionic solid which contains hydroxide ions.

Na+

OH-

NaOH(s) Na+(aq) + OH-

(aq)H2O(l)

Chemistry 120



An example of the formation of a basic solution is

Ammonia reacts with water and removes an H+ to form NH4

+, the ammonium ion,

NH3(g) + H2O(l) NH4+

(aq) + OH-(aq)

Basic solutions are formed by reaction or dissolution – formation of acid solutions by dissolution are very rare.

Chemistry 120



Hydroxide and hydronium ions will react to form water.

The presence of hydroxide and hydronium ions in water is crucial, though in pure water the concentration is very low.

Acids and bases also react to form

SALTS

2H2O(l)H3O+(aq) + OH-

(aq)

Chemistry 120



Salt formation occurs when an acid and a base neutralize each other.

Remember the reaction between hydroxide and hydronium:

HCl(g) + H2O(l) H3O+(aq) + Cl-(aq)

NaOH(s) Na+(aq) + OH-

(aq)H2O(l)

2H2O(l)H3O+(aq) + OH-

(aq)

Chemistry 120



The acid and base neutralize each other to form

water, leaving Na+(aq) and Cl-

(aq) in solution – the

saltNa+

(aq) + OH-(aq) + H3O+

(aq) + Cl-(aq)

Na+(aq) + Cl-(aq) + 2H2O(l)

+

Chemistry 120


Common acids and bases

Common acids areAcid Anion(s)

H2SO4 Sulfuric acid SO42-

(aq) and HSO4-(aq)

HX Hydrohalic acids X-(aq)

(X = F, Cl, Br, I)

H3PO4 Phosphoric acid PO43-

(aq), HPO42-

(aq), H2PO4- (aq)

H2CO3 Carbonic acid CO32-

(aq) and HCO3-(aq)

Chemistry 120


Common acids and bases

Common Bases areBase Anion(s)

MOH Group IA hydroxides M(aq)+

, OH(aq) -

(M = Li, Na, K, Rb, Cs)

M(OH)2 Group IIA hydroxides M(aq)2+, OH(aq)

-

(M = Mg, Ca, Sr, Ba)

NH3, RNH2, R2NH, R3N NH4+

, RNH3+ OH(aq)

-

R2NH2+ R3NH+

Chemistry 120


Introduction to Organic Chemistry

- Hydrocarbons

- Alkanes

- Alkenes

- Alkynes

- Functional groups

- Alcohols - Ethers

- Carboxylic Acids - Esters

Chemistry 120

Atoms, Molecules and IonsOrganic Chemistry is the study of compounds composed of carbon, with H, O, N, P, S and X (X = F, Cl, Br, I). The name stems from the isolation of these compounds initially from living bodies – plants and animals.

In 1828, Friedrich Wohler synthesized urea from ammonium cyanate, organic from inorganic.

C6

N7

O8

F9

Si14

P15

S16

Cl17

Br35

I53

Friedrich Wohler(1800-1882)

[NH4+][NCO-]

O

CH2N NH2Ammonium Cyanate Urea

Chemistry 120


Hydrocarbons

Hydrocarbons are the basic compounds of organic chemistry and are simply compounds of carbon and hydrogen.

There are three types

Alkanes Alkenes Alkynes

Alkanes are termed saturated hydrocarbons, whereas alkenes and alkynes are unsaturated.

Chemistry 120


Carbon contains four electrons in the outer shell and

can share all four with other atoms or itself.

We say that the valence of carbon is four and so the simplest hydrocarbon is CH4, methane. We draw methane as

1 H1

He2

2 Li3

Be4

B5

C6

N7

O8

F9

Ne10

H

CH H

H

H

CHH

HHH

H

H

C

Chemistry 120


The next saturated hydrocarbon or alkane is ethane, C2H6, which has the structure

Followed by propane

H

CH

H

H

CH

HH

C H

H

H

CH

H

H

CH

H

H

C

HH

H

C

H

C

HH

H

C H

H

H

C

H

H

Chemistry 120


Important hydrocarbon fragments (which are not molecules)

Methane Methyl Me- CH3-

H

CH

H

H

CH

H

Chemistry 120


Methane Methyl Me- CH3-H

CH

H

I

H

CH

H

IMethyl Iodide Me-I

Chemistry 120


Methane Methyl Me- CH3-H

CH

H

I

H

CH

H

IMethyl Iodide Me-I

Chemistry 120



Methyl Alcohol

Methanol Me-OH

H

CH

H

OH

H

CH

H

OH

Chemistry 120



Methyl Alcohol

Methanol Me-OH

H

CH

H

OH

H

CH

H

OH

Chemistry 120


Other important hydrocarbon fragments (which are not molecules)

Ethane Ethyl Et- C2H5-

Propane Propyl Pr- C3H7-

Butane Butyl Bu- C4H9-

H

CH

H H

C

HH

C

HH

C

HH

Chemistry 120


Isomers in organic chemistry

Every carbon atom has four bonds. With methane,

ethane and propane, there is only one way of

forming the hydrocarbon.

The structural formula is identical to the molecular

formula and there is only one way of writing the

structural formula, consistent with the molecular

formula.

Chemistry 120


Every carbon atom has four bonds. With methane, ethane and propane, there is only one way of arranging the atoms.

H C

H

H

H

H C

H

H H

C

H

H

H C

H

H H

C

H

H

C

H

H

H

CH H

H

H

C

HH

H

C

H

H

H

CH

HC

H H

H

C

HH

There is only one structural formula for each molecular formula

Chemistry 120


Butane, C4H10, can have more than one structural formula for the molecular formula

There is more than one structural formula for each molecular formula

H C

H

H H

C

H

H

C

H

H

C

H

H

H C

H

H

C

C

H

H

C

H

H

H

HH

Chemistry 120


Butane, C4H10, can have more than one structural formula for the molecular formula

There is more than one structural formula for each molecular formula.

THEY ARE ISOMERIC

H C

H

H H

C

H

H

C

H

H

C

H

H

H C

H

HC

C

H

H

C

H

H

H

HH

Chemistry 120


Isomers in organic chemistry

Pentane has more isomers.......

H

C HH

H C H

H C H

H C H

H C H

H

H

C HH

C H

H C H

H C H

H

H

C

H

H

H

CH H

C

HCH

H

H

C

H

H

H

C

H

H

Chemistry 120

Atoms, Molecules and IonsIn CnH2n+2, the linear alkanes, the number of isomers rises rapidly with n, the number of carbon atoms CnH2n+2 n Number of Isomers

Butane 4 2

Pentane 5 3

Hexane 6 5

Heptane 7 9

Octane 8 18

Nonane 9 35

Decane 10 75

Dodecane 12 355

Pentadecane 15 4,347

Icosane 20 366,319

Chemistry 120


The C-C chain in an

alkane may also be

joined end to end to

form a ring, the cyclic

alkanes. Whereas

linear alkanes have a

formula CnH2n+2, the

cyclic alkanes have a

formula CnH2n.

H2C

H2C

CH2

CH2

CH2

CH2

H2C

H2C CH2

CH2

CH2

H2C

H2C CH2

CH2

H2C

H2C

CH2

Chemistry 120


Alkenes and Alkynes

In the alkane series, only one electron per carbon is shared between carbon atoms. This is termed a single bond and contains an electron pair, 1 e- from each C atom.

Ethane

Here red denotes electrons from C and green denotes

electrons from H.

C

H

HH

C

H

HH

C

H

HH

C

H

HH

Chemistry 120


Alkenes and Alkynes

In an alkene or alkyne, a C atom shares two electrons with a neighboring atom to form a double bond or triple bond containing 4 or 6 electrons.

Ethene

(Ethylene)

Ethyne

(Acetylene)

C

H

H

C

H

H

C

H

H

C

H

H

CH CH C HC H

Chemistry 120


Functional groups

We can expand the number of compounds possible by binding different functional groups to a hydrocarbon fragment such as methyl or ethyl.

Alcohols -OH Alkyl halides -X

Amines -NH2

Chemistry 120


Functional groups

Methane Methanol Methylamine Chloromethane

H

CH

H

H

H

CH

H

H

H

CH

H

OH

H

CH

H

OH

H

CH

H

Cl

H

CH

H

Cl

H

CH

H

Cl

H

CH

H

Cl

Chemistry 120


Functional groups

Replacing a –CH2– group in an alkane gives an ether

Pentane Diethyl ether

H C

H

H H

C

H

H

C

H

H

C

H

H

C

H

H

H3C

CH2

CH2

CH2

CH3

H C

H

H H

C

H

O

H

C

H

H

C

H

H

H3C

CH2

O

CH2

CH3

Chemistry 120


More complex functional groups

Introducing a double bond to oxygen gives a whole series of new classes of compoundsKetonesPentane 3-pentanone 2-pentanone

H C

H

H H

C

H

H

C

H

H

C

H

H

C

H

H

H3C

CH2

CH2

CH2

CH3

H3C

CH2

CH2

C

CH3

O

H C

H

H H

C

H

C

H

C

O

H

C

H

H

H

12345

H C

H

H H

C

H

C

O

H

C

H

H

C

H

H

H3C

CH2

C

CH2

CH3

O

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Chemistry 120


More complex functional groupsAldehydes

If the C=O function is at the end of the chain, then the compound is termed an aldehydePentane Pentanal

H C

H

H H

C

H

H

C

H

H

C

H

H

C

H

H

H3C

CH2

CH2

CH2

CH3 H3C

CH2

CH2

CH2

C

H C

H

H H

C

H

C

H

C

H

C

O

H

H

H

O

H

Chemistry 120


More complex functional groupsCarboxylic acids, esters and amides

These classes of molecules contain the group

C

O

Z Z = -OH, -OR, NR2, -X

Chemistry 120


More complex functional groupsCarboxylic acids, esters and amides

Z varies according to

C

O

OH

C

O

OR

C

O

NR2Carboxylic acid

Carboxylic Ester

Carboxylic Amide

C

O

X Carboxylic Acid Halide

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Chemistry 120 Chemical Composition of the World: Atoms 101 “indivisible, uncuttable” All matter is composed of atoms which cannot be further split