MUHAMMAD FAHAD ANSARI 12 IEEM 14

2. Environment
By
MUHAMMAD FAHAD ANSARI
12 IEEM 14

3. Why should we study Chemistry?
Most of the World around us has a chemical basis.
Consider many ways in which chemistry effects us.
 Our body is a complex aggregate of chemical substances.
 We depends on chemical processes for our life, because
chemicals provide food, heat, light and the.
 Other essentials such as cloths, building material,
medicines, dyes, explosives are also made of chemicals.
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4. Chemistry
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6. What is Chemistry?
The science that deals with matter; its
composition; its properties; the changes in
composition that it will undergo; its relationship
to energy; and the laws, principles, theories, and
concepts that describe, interpret, and predict its
behavior and basic nature.
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7.  Organic Chemistry is simply the chemistry of
the compounds of the element carbon. In other
words the properties of organic compounds are
largely a result of the covalent bond.
Except the carbon-containing compounds such as
carbon dioxide, the carbonates, bicarbonates, and
carbides.
 Biochemistry: The chemistry that deals with the
substances and reaction in living organisms.
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8.  Electrochemistry: the chemistry dealing with the
effects of electricity on chemical reactions and the
production of electricity through chemical
processes.
Chemical reactions involve an electron exchange
between the reactants. These reactions are called
oxidation-reduction reactions or electrochemical
reactions.
There are two different classes of electrochemical
reactions: those that produce electrical energy
and those that are produced by electrical energy.
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9.  Analytical Chemistry: deals with the analysis of
compounds and mixtures. Samples are separated
into their component parts to determine what is
present (qualitative) and how much (quantitative
analysis).
 Stoichiometry: refers to measurements and
relationship involving substances and mixtures of
chemical interest.
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10. Nuclear Chemistry
The primary functions of atomic nuclei in the phenomena
we have considered in establishing the masses of atoms
and molecules and in furnishing a center of positive
charge to keep electrons in position.
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11. Periodic Table
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12.  Metals: They are good conductors of electricity;
they contain only one or two weakly electrons in
their outer energy levels.
 Non-metals: They have relatively strong
attraction for the electrons in their outer energy
levels.
 Metalloids: The elements whose properties are
intermediate between those of the metallic and
non-metallic elements.
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13.  Atomic Number: The number of protons in the
nucleus of its atoms.
 Atomic Mass: The sum of protons and neutrons
in an atom.
 Equivalent weight: The molecular weight of a
substance divided by its combining capacity in the
reaction.
 Valence: The number of electrons an element
gains, loses, or shares in forming a compound. 13

14. Electronegativity
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19. Electro-negativity
The bonds between two elements can be purely
ionic, purely covalent, or anywhere in between
depending on the elements involved.
 The electro-negativity expresses the power of an
atom in a molecule to attract shared electrons.
 The electro-negativity values come from
measurements of the strength of bonds between
atoms and from measurements of the amount of
electrical energy required to remove an electron
from an atom of an element.
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20.  Fluorine (F) which has the strongest attraction for
electrons of all the reactive elements is assigned
an electro-negativity value of 4. All other elements
are compared to fluorine.
 According to Pauling (1901), if the difference
between the electro-negativity values of the two
elements is 2.0 or more, the bond is mainly
ionic. If the electro-negativity difference is less
than 2.0, the bond is mainly covalent.
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21. Bonding between Elements
 Ionic Bond: The electrostatic attraction that
exists between positive ions formed when one
atom loses electrons and negative ions formed by
the atoms that gain the electrons.
 Covalent Bond (Coordinate Covalent Bond):
A bond between two atoms in which they are
overlapping orbitals and sharing a pair of
electrons, both of which originally belonged to
only one of the atoms.
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22.  Ionic bond with: exchange of electrons to form
stable octet; bond between a metal and nonmetal;
example: NaCl, CaF2
 Covalent bond with: sharing of electrons to form
stable octet; bond between nonmetals; example:
Cl2, N2
 Polar covalent bond with: unequal sharing of
electrons to form stable octet; example: H2O, NH3
 Metallic bond with: sea of mobile electrons;
bond between metals; example: Cu, Ag 22

23. Polar and Non-Polar Molecules
 Any diatomic molecule that has a non-polar bond
is non-polar. Example: All diatomic molecules: Cl2,
N2, O2, etc… Otherwise, it will generally be polar.
 Molecules that consist of 3 or more atoms are
generally polar unless the following condition is
met:
If the central atom has no lone pairs and is
surrounded by atoms of one element, then the
molecule will be non-polar, for example, CO2.
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24. Organic and Inorganic Compounds
The distinction between the compounds found in
the earth associated with rocks and soil and those
associated with living organisms.
 The two groups of compounds differ in their
occurrence and in many of their properties.
 The compounds associated with living organisms
called organic compounds, and the earthy
compounds are called inorganic compounds.
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25. Table- Properties of
Ionic and Covalent Compounds
Inorganic (Ionic) Organic (Covalent)
Compounds Compounds
1 Solids, often crystalline, May be solid, liquid, or gas, depending on the size of
relatively hard and brittle the molecules and the degree of intermolecular
attraction (polarity and ability to form hydrogen
bonds)
2 Relatively high melting and Relatively low melting and boiling points, depending
boiling points primarily on the size of the molecules and the
amount of intermolecular attraction
3 Relatively soluble in water and Relatively insoluble in water and soluble in organic
insoluble in organic (non liquids; polarity and ability to form hydrogen bonds
polar) liquids greatly increases water solubility
4 Electrolytes-solutions conduct Most are non electrolytes
electricity
5 Relatively stable to heat Relatively unstable to heat
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