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2nd secondary

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Chemistry
Second Secondary

2nd secondary

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Contents
Chapter One:
Atomic structure
...
youtube
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https://www
...
com/watch?v=hePb00CqvP0

Chapter Three:
Bonds and forms of molecules
...
youtube
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https://www
...
com/watch?v=-0N1ZZZRM48

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General objectives of chapter one:
1-Recognize the historical background of atomic structure
...

3-Discuss the Rutherford’s atomic model
...

5-Define the reasons of inadequacy of Bohr’s model
...

7-Explain the concept of electron cloud and orbitals
...

9-Distribute electrons of any atom considering the building
up principle and hund’s rule
...


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Chapter one

Structure of the atom
Atomic structure
1-Democritus’s (Greek philosophers) idea:
Any piece of matter can be divided into smaller parts and each part can be
subdivided into smaller parts which can't be divided this part is called Atom
...

b- He supposed that all matters composed of 4 constituents which are (water,
air, dust and fire) and postulated that the cheap metals such as iron or copper
can be changed into precious ones like gold by changing the percentage of four
constituents
...

B-He was the 1st scientist to define the element as pure simple substance which
Cannot be analyses into simple one by normal chemical methods
...

2- Every element consists of very small dense atoms which can’t be divided
...

4- Atoms of different are different
...


5 – Thomson’s model of the atom:
The scientist Thomson carried out many experiments on the electric
discharge through gases from which he had discovered the cathode rays
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Cathode- rays experiment
(Discovery of the electron)
High voltage 10000
vollts

Anode

Cathode
To vacuum pump

a- All gases under normal conditions of pressure and temp
(76 cm
...
25c) don't conduct electricity
...
These rays were named by (Cathode rays)
...

2) Transfers in straight lines glowing the glass facing the cathode
...

4) Have a thermal effect
...

6) Cathode rays don’t change by changing either cathode material or type
of the gas, which proves that cathode rays take part in the structure of
all substances
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Metal sheet covered
with ZnS

Gold foil
Source of alpha
particles

1– He allowed alpha particles to hit a metallic plate lined with Zinc sulphide
(glows when hits with alpha rays)
2– On placing a gold foil in the front of alpha rays he concluded the
following from the following observation
...

1- A very small percentage of alpha
particles reflected back to
appears as flashes on other side of
sheet
...


2- Most of the atom is a space not
solid as explained by Dalton
and Thomson
...

4- The dense parts of the atom,
which concentrate in it most
mass, have same charge of
alpha particle (+ve) which
called nucleus of the atom
...


1- The Atom:
Although it has very small size but it has a complicated structure that
resembles the solar system in which electrons revolve around the
central nucleus in orbits as planets revolve around the sun
...
Located in the centre of the atom with
(+ve) charge
...
Most mass of the atom is
concentrated in the nucleus as mass of e is very small and can be
neglected
...

2- No of electrons (-ve) equals no of protons (+ve) so the atom is
electrically neutral
...

b- Centrifugal force due to velocity of electron around the nucleus
...

Explain: Structure of the atom in the view of Rutherford
...

2- Atom is electrically neutral as no of p+ s equals to no of e's
...

4- Electrons orbit the nucleus in a rapid movement without gaining or losing
energy
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6- Each electron in the atom has a definite amount of energy depending on
the distance between is E
...
This energy increases as its radius
increases
...
Each level has energy expressed by a completely no called principle Q
...


Ex: The 1st E
...
no = 1
The 2nd E
...
no = 2
8- If when atom is excited by heating (Quantum) or by electric discharge
the electron will transfer to a higher E
...
The excited electron in the higher E
...


 Remarks:
1- The quantum: Is the amount of energy gained or lost when an electron
jumps from one E
...

2- The difference in energy between levels (Q) is not equal i
...
the difference in
this energy decreases further from the nucleus
...

3- The electron does not move from its level to another unless the energy
absorbed or emitted is equal to the difference in energy between 2 levels i
...

one quantum
...
Q can't be divided or doubled

Give reason: It is wrong to say that e' to be transferred from E
...
L (M)
needs amount of energy equals 2 quantum
...
L to higher ones
...

2- He introduced the idea of quantum no to detect energy of electrons in
energy levels
...


Disadvantages (Inadequacies) of Bohr's theory:
1 – If failed to explain the spectrum of any other element even that of He
except hydrogen (Simplest Electronic System)
...

3– He postulated that it is possible to determine precisely both speed and
location of an electron at the same time
...

4– He described the electron when moving in a circular planer orbit, which
means that hydrogen atom is planer
...


Bohr's Theory
The atomic spectrum
Studying and explaining the atomic spectrum was the key to his atomic
structure in 1913 and he was deserved Noble Prize in 1922
...

2 – By using spectroscope we find that this light consists of a fixed number of
colored lines called line spectrum
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By exp
...


N
...


The principles of Modern Atomic Theory:
1 – Dual nature of electron
...

3 – Finding the mathematical expression, which describes the wave motion
of electron, its shape and its energy?
-------------------------------

1 – The dual nature of the electron
The experimental data showed that the electron has a dual nature i
...

a) It is a material particle
...


* De Broglie principle:
Every moving body (such as electron or the nucleus of an atom or whole
molecule) is associated with (accompanied by) a wave motion (or matter
waves) which has some properties of light waves
...
We can only say that it is
probably to a greater r lesser extent to locate the electron in this or in that
place
...

3
...

 The electronic motion around nucleus has wave properties therefore the
position to use the term electron cloud to describe any orbital
...
"
 The difference between the orbit and orbital concepts according to both
Bohr and the wave mechanics theories:
Bohr s theory
Schrodinger s wave mechanics theory
 It is a circular planer orbit with
 It is an electron cloud used to
particular radii
describe any orbital
 Electron cloud the regions of
high density of dots represent
the region of high probability of
finding the ( e ) from which it is
Bohr's orbit
possible to define the atomic
radius
Probabili
ty of
finding
the
electron

Schrodinger's wave mechanics
theory

Distance from
the nucleus
R

Probabilit
y of
finding
the
electron
Distance from the
nucleus

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 The mathematical solution of the Schrodinger equation introduced four
numbers which are called quantum numbers
...
Besides, they define the energy, shape
and direction of orbital
...
no (n)
...
no (ℓ)
...
no (mℓ)
...
no (ms)
...
levels their number in the heaviest known atom in
the ground state is seven
...
level = two times the square of
the level no (2n2)
...
L
K
Is filled with
2 electrons
nd
-2 E
...
L
M
Is filled with
18 electrons
th
-4 E
...
However,
the atom becomes unstable if no of electrons exceeds 32 electrons on any
level
...
Subsidiary Q No (ℓ):
1- Used to detect the no of sub levels in each E
...

2- The energy sub levels take the symbols s, p, d, f
...
When he used a spectroscope, which has a high resolving
power, he found that the single line (which represents electron transition
between two different energy levels) is indeed a number of fine spectral
lines which represents electron transition between very near energy
levels (sublevels)
...


-1st E
...
L
-3rd E
...
L

K
L
M
N

has 1 sub level
has 2 sub level
has 3 sub level
has 4 sub level

1s
2s, 2p
3s, 3p, 3d
4s, 4p, 4d, 4f

N
...
level is not equal
...
levels also differ in energy
...


Ex: 4d>3d

4p>3p>2p

 There is a small difference in the energy between sub-levels
...
Magnetic Q No (m):
Detected by Zeeman when he exposed spectral line to strong magnetic field, he
found that each line divides into many lines, so he concluded that each E
...


- Magnetic Q No(mℓ ) is characterized by:
1- Used to detect no of orbitals in each E
...

2- Sublevel (S) has one orbital of spherical symmetrical shape
...

 Each orbital (Px,Py,Pz ) is perpendicular to the other two
...
e point of zero electron
y
density
...

5- Sublevel (f) has 7 orbital
...

Ex: px = py = pz
7- No of orbitals in each E
...
level = n2
...
No (ms):

 Detects the direction in which the electron spins around its axis during its
rotation around the nucleus
...

 It has only two possible values + 1/2 – 1/2




Give reason: Each orbital carries 2 electrons although they are negatively
charged
...
L, sub levels
orbitals and no of electrons:
1- No of energy sublevels = order of principle level (n)
...

The stereo structure of any molecule is represented by the following formula
(AXnEm )

III – Co-ordinate bond:-

It is formed between a donor atom having a lone pair or more of electrons and
an acceptor atom having a vacant orbital
...

-also types of bonds in the last examples are polar covalent and co –
ordinate bonds
...

Definition with examples
...

**So hydrogen atom acts as a bridge to bind molecules together
...
5),
while
Electronegativity of hydrogen is 2
...
So oxygen atom will carry a -8
charge,
While hydrogen atom will carry a (+ s) charge
...

2  

O

2  

H

O

H

 ofHwater (H2O)
 H is very small (18) but it
Give reason: Although molecular weight
Existed in a liquid state and boils at 100 C, while molecular weight of
Hydrogen sulphide (H2S) is (34) but it exists in a gaseous state and boils
at (-61 C)
...
N
...


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- Hydrogen Bond in HF:

Give reason: Although sugar is covalent compound but it dissolves in water
...


- Properties of hydrogen bond:
1- Strength of H-Bond depends on the difference in electronegativity
increases, the strength also increases and the boiling point will be high
as in water
...

3- H-Bond is much weaker than covalent bond
...

B- Closed ring
...
L
...
j)

Covalent bond
1A
418

C- Open net
...
"
 The free valency electrons of the outer shell are associated together
forming an electron cloud which decreases the repulsion force between
(+ve) ions in the metallic structure
...
As the no of free valence electrons
increases, the atoms of metal will be strongly bonded, so the metal will be
harder, of higher melting & boiling points and higher thermal and
electrical conductivity
...


-

Answer: In case of Na: due to weak metallic bond which depends only on
one electron from ns, while in case of Al: due to strong metallic
bond which depends on three valency electrons of ns, np
...

 Polar compounds as HCL dissolve in polar and non polar solvents
...

2- Co-ordinate bond
...

(2) Give reason:
1
...

2
...

3
...

4
...

5
...

(3) Write the scientific name:
1- A bond is formed by the overlapping of orbitals side by side
...

3- An ion formed by combination between water and proton
...

5- The bond which is formed between two atoms having the same
electronegativity
...
Sigma and Pi Bonds
...
Covalent and ionic compounds
...
- Methane
...

(6) The following elements: A1 , B11 , C17
1- Show how can you get:
a) Ionic compound
...

c) Pure covalent compound
...
For the elements 9A, 10 B, 11C, which of the following can happen?
a) B combines with C
...


b) B can react with itself
...


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2
...
If two atoms combine with each other,
what is the type of the bond that will be found in the molecule?
a) Metallic
...


b) Co-ordinate
...


3
...

c) Polar bonds
...

d) Solubility
in
polar
solvents
...
The bond in a hydrogen fluoride molecule is a polar covalent bond because
the two atoms differ in:
a) Their position in the periodic
table
...


b) Electronegativity
...


5
...

c) A linear shape
...

d) Two orbitals and a linear shape
...
In the acetylene molecule we notice that:
a) Between the two carbon atoms there is a double bond, one is sigma the
other is pi
...

c) Each carbon atom is SP hybridized
...


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a

Monthly Exam
...


B- Give reasons:
1- Zinc oxide is from amphoteric oxides
...

(Second question)
(A)
Write the scientific term for each of the following:
1- A bond formed as a result of overlap of two atomic orbitals by head to head
...

(---------------)
3- A bond is formed when hydrogen atom lies between two atoms of high
electronegativity (------------)
B- Show the oxidation and reduction in this reaction :
2FeCl3

2FeCl2 + Cl2

(Third question):
Compare between ethylene & acetylene
...

B- What is meant by?
1
...
Recognize the alkali metals and their electronic configuration
...
Conclude methods of extraction of alkali metals from their ores
...
Practice some experiments for the identification of basic radicals
...
Define the oxidation number of Nitrogen in different compounds
...
Compare different types of nitrogenous fertilizers
...
Know the economic importance of the fifth group elements
...
Recognize scientists’ efforts in serving humanity
...

2- P – Block elements: elements of group V
...

1- Lithium
Li
no using
2- Sodium
Na
Rock salt (NaCl )
3- Potassium
K
in sea water KCl and carnalities
(KClMgCl2
...

4- Rubidium
Rb
no using
5- Cesium
Cs
no using
6- Francium
Fr
Radioactive element it is produced
from disintegration of actinium
227
89Ac

223
87Fr

+ 2He4

General properties of elements of group 1A
1- Every element consists of one electron in the outer most energy level
they are characterized by:
A- Every element lies in the beginning of new period
...

C- They are chemically very active due to the presence of one electron in
the outer mast energy level which can by easily lost and they have very
low ionization potential
...

2- Most of their compounds are ionic: They can lose the electrons from their outer most energy level easily to
form positive ions which have the same electronic structure of noble
gas which precedes it
...

4- They are most (soft) metals with low melting and boiling points due to
the decreasing in the strength of the metallic bond between atoms
since they have only one electron in the outer most energy level
...

6- Elements of group (1A) are considered of the highest electropositive
metals because they can easily lose the valency electron
...

6- They have characteristic colors when the atom gains an amount of
energy which is sufficient to transfer electrons to higher energy levels
they give a characteristic colors: dry test
Element
Lithium
Sodium
Potassium
Calcium

Color
Crimson
Golden yellow
Pale violet
Bluish violet

7- They are kept under liquid hydrocarbons
...

8- Action of atmospheric air:
All elements lose their metallic luster because they reacts easily with
air to form metal oxide
...

6 Li + N2
2 Li3N
G
...
F:
Lithium nitride is used a fertilizer?
This is because lithium nitride decomposes when the soil is irrigated
giving ammonia (fertilizer)
...

10- Reaction with oxygen:
4 Li + O2
2 Li2O
2 Na + O2
Na2O2
2 K + O2
2 KO2
Potassium super oxide is used in (submarines and aero planes) in closed
atmospheres because it reacts with exhaled carbon dioxide giving oxygen
required for breathing:
C
2K2CO3 + O2
u
cl
11- Reaction with acids
u
2Na + 2HCl
2NaCl + H2
u
cl
4KO2 + 2CO2

2
12- Reaction with
hydrogen (to form hydrides)
C
2Li + H2
2LiH
at
2Na + H2
2NaH

...
B: Hydrides are ionic compounds because they produced from the
reaction of element with hydrogen such as NaH , LiH
...

2Na + Cl2
2NaCl
2K + Br2
2KBr
14- Reaction with other non – metal:
2Na +S
Na2S (Sodium sulphide)
3K + P
K3P (Potassium phosphate)
15- Action of heat on metal carbonates:
All alkali metals carbonates do not decompose when heated except
Lithium carbonate
...

Elements of group (1-A) are extracted from their ores by electrolysis
because they strongest reducing agent and can not be reduced from their
ores by any reducing agents other than electrolysis
...


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Commonly used sodium compounds
1- sodium hydroxide NaOH
a) preparation in industry :
By the electrolysis of sodium chloride solution
b) Properties:
1- A white hygroscopic solid compound
2- It has a corrosive effect on skin
3- It dissolves easily in water forming an alkaline solution through
an exothermic dissolution
3- it react with acids forming the sodium salt of the acid and water
NaOH + HCL
2NaOH + H2SO4

NaCL + H2O
Na2SO4 + 2H2O

Uses:
1- NaOH used in many industries as : Soap , synthetic silk and paper
2- it used in purify petrol
3- detection of basic radicals ( cations):Detection of of copper II (Cu++)
Salt solution + NaOH it gives a blue p
...
t turns black by heating
CuSO4 + 2NaOH
Cu (OH)2

∆

Cu (OH) 2 +Na2SO4
CuO + H2O

Detection of aluminum AL3+
Salt solution + NaOH gives a white p
...
t dissolves in excess of NaOH
AlCl3 + 3NaOH
Al (OH) 3 + NaOH

3NaCl + Al (OH) 3
NaALO2 + H2O

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2- Sodium carbonate Na2CO3
The hydrated salt Na2CO3
...
its solution has an
alkaline effect
2- it is not affected by heat i
...
it melts without decomposition
3- it react with acid , and CO2 evolves
Na2CO3 + 2HCl
Uses:
1- paper industry
2- water softening
3- textile industry
4- manufacture of glass

2NaCl + CO2 + H2

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Elements of group (5A)
Nitrogen N7 : non – metal – diatomic – gas in atmospheric air 80%
...

Arsenic As33 : metalloid – Arsenic sulphide As2S3 – vapor (4atom As4)
Antimony Sb51 : metalloid–Antimony sulphide Sb2S3 – vapor atoms Sb4
Bismuth Bi83 : metal forming a crystal lattice – weak to conduct electricity
– vapor (2atom)

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General properties
1- Oxidation number : Elements of group [5 – A] have several oxidation
numbers because they gain electrons from 1 to 3 through covalent
sharing or electrons from 1 to 5 electron and reach to the stability state

...

3- With hydrogen: Most of elements of this group reacts with hydrogen to
form hydrides such as NH3 , PH3 , phosphine , Arsine AsH3
These compounds (NH3- PH3) can form coordinate bonds due to presence
of pair of electrons in valence shell so it can give this electrons to the
outer atoms or ions to form coordinate bond
NH3 + H+
NH4 , PH3 + H+
PH4
These compounds are basic because atom of element has one pair of
electrons donated to positive proton of hydrogen which is found in the
molecule of water therefore the negative hydroxyl group separated from
molecule of water
...

- The thermally stability and the solubility in water are decreases with
increasing the atomic in this group (NH4+) is more polarity than (PH4+) is
more polarity than (AsH4 +)

Allotropy
It is the presence of the element in more than one form having the same
chemical properties but different physical properties
...


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Forms:
Solid non – metal
Phosphorus
Arsenic
Antimony

Allotropic forms
White – red – violet
...

Yellow – black
...

1- The main method ( from the atmospheric air )
2NaOH + CO2
2Cu + O2
∆

Na2CO3 + H2O
2CuO

2- From the chemical compounds:
By heating a mixture of sodium nitrite and ammonium chloride
solutions
...


nitrogen with oxygen
2NO

The color of nitric oxide (colorless) turns brown when it is exposed to
atmospheric because nitric oxide is oxidized to form nitrogen dioxide
when it exposed to air
...

CaC2 + N2 ∆
CaCN2 + C
CaCN2 + 3H2O
CaCO3 + 2NH3

Important nitrogen compounds
1- Ammonia gas (NH3)
Preparation ammonia gas in lab
By heating a mixture of ammonium chloride and slaked lime (Ca (OH)2)
2NH4Cl + Ca (OH) 2 ∆
CaCl2 + 2NH4OH
∆
2NH4OH
2NH3 + 2H2O
Amm
oniu
m
chlori
de +
slake
d
lime

NH3

Quick
lime
for og
Preparation
drying
ammonia
in lab

Ammonia gas is dried by passing it in quick lime
(CaO) because quick lime dose not react with
ammonia gas conc
...

Ammonia gas is collected by down – word
displacement of air because it is lighter than air or
density of NH3 is less than air
...

2- It is easily soluble in water to from NH4OH which turns the red litmus
solution into blue
...

1- Setup the apparatus as show in
figure the lower bottle contains
litmus solution
...
R
...

N2 + 3H2
2NH3
2- Nitric acid HNO3
1- Preparation of nitric acid in lab
2KNO3 + H2SO4

∆

K2SO4 + 2HNO3

The apparatus for preparation of nitric acid does not contain rubber
stopper because the vapors of nitric acid damage the organic materials as
rubber
...
dose not exceed more than 100ºC because the
acid is decomposed thermally
...

b- The presence of some impurities in the metal
...

d- Temperature of reaction:

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- Metals above hydrogen
...

D
3Cu (NO3)2 + 4H2O + 2NO
il
Cu + 4 HNO3 C
Cu (NO3)2 + 2H2O + 2NO2
o
n nitric acid although
Copper reacts with
c
it is below hydrogen
in the electro chemical series because the acid reacts
with copper as oxidizing agent i
...
it oxidize the copper to copper oxide
which reacts with acid
...
and canc
...


Dilute HNO3
Nitric oxide gas
colorless is formed that
turns in to nitrogen
dioxide gas
...
HNO3
Nitrogen dioxide gas
(reddish brown fumes)
are formed
...


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Economic importance of 5th group elements
Nitrogen: The manufacture of Ammonia – nitric acid – nitrogenous
fertilizers – used in filling of car tires – used in filling chips
packaging bags
...


Arsenic: It is used as a preservative substance for wood due to its
poisonous effect on insects, bacteria and fungi
...


Bismuth: Alloys of bismuth, lead, cadmium are characterized by their
low melting point which are used in manufacturing of electric
fuses
...

2
...

4
...


The reaction between nitrogen and lithium, then adding water
...

Adding dilute cold sulphuric acid on sodium peroxide
...

Reaction between lithium and hydrogen, then adding water
...
Oxygen from sodium nitrate
...
Ammonia gas from lithium
...
Oxygen from potassium
...
Nitrogen dioxide from conc
...

5
...

Give reason for:
1
...

2
...

3
...

4
...

5
...

6
...

7
...

8
...

9
...

10
...

How to differentiate between:
1- Copper sulphate and aluminum sulphate
2- Conc

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