Review

Inorganic Chemistry

Chemistry 20

More than 20 million compounds are composed of these 116 elements.

Element: is a substance consists of identical atoms.

Cannot be divided by chemical & physical methods.

Carbon, Hydrogen, Oxygen

116 elements – 88 in nature

main-group elements: 1A to 8A

transition elements: 1B to 8B (3 – 12)

inner transition elements: between B3 & B4 (58 to 71 and 90 to 103)

Column: same properties (main group)

row or period

nonmetals

metals

metalloids

Classification of the elements

metals: solid (except mercury), shiny, conductors of electricity, ductile, malleable

nonmetals: solid, liquid or gas, do not conduct electricity (except graphite)

metalloids: between metals and nonmetals

to

n=1

n=2n=3 n=4

n=5

E1 E2 E3 E4 E5

Bohr model

Principal energy levels or Shell

324

183

82

21

Maximum number of electrons

Level

Lower energy

Higher energy

Sublevel: s p d f

Orbital: is a region of space and it can hold 2 electrons (max).

s p d f

2 2+2+2=6 2+2+2+2+2=10 2+2+2+2+2+2+2=14

Level OrbitalsMaximum number

of electrons

1 1s 2

2 2s, 2p 2 + 6 = 8

3 3s, 3p, 3d 2 + 6 + 10 = 18

4 4s, 4p, 4d, 4f 2 + 6 + 10 +14 = 32

3

2

3d3p

3s2p

2s

Principal energy level Orbitals

En

erg

y

Ord

er

of

filli

ng

1 1s

Orbital box diagrams

H (1)1s

1s1

Electron configuration

1sHe (2) 1s2

Li (3)

1s 2s

1s2 2s1

C (6)

1s 2s

1s2 2s2 2p2

2px 2py 2pz

Electrons configuration: description of the orbitals that its electrons occupy.

Valence electrons: outer-level electrons

Valence level: outer level

Cl (17) 1s2 2s2 2p6 3s2 3p5 7 valence electrons

Ar (18) 1s2 2s2 2p6 3s2 3p6 8 valence electrons

C (6) 1s2 2s2 2p2 4 valence electrons

Ne (10) 1s2 2s2 2p6 8 valence electrons

Noble gases Filled valence levels

Lewis dot structure

H He Li C Cl

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

Level 1

main-group elements

1A – 8A

Maximum 2 electrons in valence level

Hydrogen and Helium

Other Levels Maximum 8 electrons in valence level

1. Ionic bonds

2. Covalent bonds

Chemical Bonds

Goal of atoms Filled valence levelNoble gases

(Stable)

Na+: 1s2 2s2 2p6

+ e-

Na: 1s2 2s2 2p6 3s1 Ne: 1s2 2s2 2p6

Ar: 1s2 2s2 2p6 3s2 3p6

Octet rule

Octet rule

Goal of atoms Filled valence level

+ e-

Ar: 1s2 2s2 2p6 3s2 3p6

Noble gases (Stable)

Cl: 1s2 2s2 2p6 3s2 3p5 Cl-: 1s2 2s2 2p6 3s2 3p6

Na+: 1s2 2s2 2p6

+ e-

Na: 1s2 2s2 2p6 3s1 Ne: 1s2 2s2 2p6

Ionic bonds

Metal-Nonmetal

Na: 1s2 2s2 2p6 3s1 Cl: 1s2 2s2 2p6 3s2 3p5

AnionCation

Na+: 1s2 2s2 2p6 Cl-: 1s2 2s2 2p6 3s2 3p6

Covalent bonds

Nonmetal-NonmetalMetalloid-Nonmetal

Sharing ofvalence electrons

Lewis Dot Structure

H He Li CAl N Cl

H H Or H H

Or Cl H

Lewis Structure

HCl

Cl: 1s2 2s2 2p6 3s2 3p5

H: 1s1 He: 1s2

Ar: 1s2 2s2 2p6 3s2 3p6

Covalent compounds

H – C – H

–OCH2O H C H

OH – C – H

–O

H C H

O –

Correct

H C HH

HH – C – H

–H

–

H

CH4

H – N – H

–HNH3 H N H

H

H C C H

C – C

C2H4

H H

HH

H

H

H C C H

C = C

H H

HH

H

H

H C C H

H – C – C – H

C2H2H C C H

H – C C – H

Correct

Electronegativity

A measure of an atom’s attraction for the electrons

Covalent bonds

Nonpolar covalent bond: electrons are shared equally.

Polar covalent bond: electrons are shared unequally.

H Clδ+ δ-

Dipole

Polarity

1. Molecule has polar bonds.2. Its centers of δ+ and δ- lie at different places (sides).

O = C = O

δ- δ+ δ-

nonpolar molecule

H – C – H–H

–

H

δ+

δ+

δ+

δ+

δ-

C

=O

H Hδ+

δ-

polar molecule

N

HH H

δ-

δ+

Intermolecular Forces

London dispersion forces

Dipole-dipole interaction

Hydrogen bonding

Ionic bondsCovalent bonds<

Intramolecular (Bonding) Forces

Intermolecular Forces

London dispersion forces

Attractive forces between all molecules

Only forces between nonpolar covalent molecules

2+

No PolarityOriginal Temporary

Dipole

δ- δ+

+2+

HeHe

Original Temporary Dipole

Induced Temporary Dipole

__ _ _

He He

2+_ ___ 2+

δ- δ+He

__ 2+

δ- δ+He

__ 2+

Dipole-Dipole Interactions

Attractive force between two polar molecules

stronger than London dispersion forces

boiling point ↑

Hydrogen Bonds

stronger than Dipole-Dipole and London dispersion forces

surface tensionHigh boiling point

H2O

Between H bonded to O, N, or F (high electronegativity) → δ+and a nearby O, N, or F → δ-

Hydrogen bonding

CH3COOH

Acetic acidδ-

δ+

Factors that affect boiling point:

1. Intermolecular forces:

London dispersion forces < Dipole-Dipole interactions < Hydrogen bonds

3. Molecular shape: With the same molecular weight.

linear CH3-CH2-CH2-CH2-CH3 > spherical CH3-C- CH3

_

_

CH3

CH3

2. Number of sites for intermolecular interaction (surface area):

Larger surface areas (more electrons) more sites for L.D.F b.p.

CH3-CH2-CH2-CH2-CH3 > CH3-CH2-CH3

Boiling point