This document provides an overview of carbon and organic chemistry topics. It discusses the structure and properties of carbon, including its ability to form covalent bonds and exist in different allotropes like diamond, graphite and buckminsterfullerene. Carbon's versatility is explained by its properties of catenation and tetravalency. The document outlines saturated and unsaturated hydrocarbons, and describes how carbon can form chains, branches and rings. Lewis structures are introduced as a way to represent bonding. Homologous series are defined as compounds with the same functional group substituting for hydrogen in a carbon chain.
Historical philosophical, theoretical, and legal foundations of special and i...
Carbon: Versatile Element for Life
1.
2. Topics To be Covered
Introduction to Carbon
Bonding in Carbon (Covalent Bond)
Allotropes of Carbon
Versatile nature of Carbon
i)Saturated and Unsaturated hydrocarbons
ii)Chains, Branches and Rings
iii)Homologous Series
3. Introduction
What is carbon?
Carbon is a chemical element with atomic number 6
and mass 12 and it is a tetravalent atom
Compounds are of two types:-
i)Organic
ii) Inorganic compounds
Organic compounds are made by carbon and thus
stand as a base for all living organisms
4. The Covalent Bond
Covalent Bond in carbon :-
The atomic number of carbon is 6 and its electronic
configuration is 2, 4. To attain a noble gas configuration it
requires four more electrons in its valence shell.
It is difficult for an atom of carbon to either gain or lose electrons
as it would be difficult to hold extra electrons and would require a
large amount of energy to remove four electrons.
Carbon attains the noble gas configuration by sharing its valence
electrons with other atoms . Such mutual sharing of electrons
between atoms to attain a stable noble gas configuration is
called Covalent bonding.
Atoms of other elements like hydrogen, oxygen, nitrogen,
chlorine also show sharing of valence electrons.
5. Types of Covalent Bonds
Depending on the number of electron pairs shared,
covalent bond is of three types :
i)Single Covalent Bond: Single covalent bond is formed
because of sharing of two electrons,i.e one pair .Example
: Hydrogen,Chlorine,Methane.
ii)Double covalent bond: Double bond is formed by
sharing of four electrons,i.e two pairs of electrons.
Example : Oxygen molecule,Carbon Dioxide molecule.
iii)Triple Covalent Bond: Triple covalent bond is formed
because of the sharing of six electrons, three pairs of
electrons. Example :Nitrogen,C2H2
6. Properties of Covalent bonds
Properties of Covalent Bonds.
– Covalently bonded molecules have low
melting and boiling points .
–comparatively weaker intermolecular forces,
unlike ionic compounds.
– These molecules are generally poor
conductor of electricity since no charged
particles are formed.
7. Allotropes of Carbon
There are 3 main allotropes of carbon
i) Diamond
ii) Graphite
iii) Buckminsterfullerene(C60)
8. Versatile Nature Of Carbon
2 Main Properties which make Carbon a unique atom:-
1. CATENATION is property of carbon atom to form bond
with other atoms of carbon. Like carbon, silicon forms
compounds with hydrogen upto seven or eight atoms of
silicon called silanes.
2.TETRA VALENCY : Having a valency of 4, carbon atom is
capable of bonding with atoms of oxygen, hydrogen, nitrogen,
sulphur, chlorine and other elements. Since it requires four
electrons, carbon is said to be tetravalent.
The smaller size of carbon atom enables nucleus to hold the
shared pair of electrons strongly, thus carbon compounds are
very stable in general.
9. Saturated Hydrocarbons
Saturated Compounds : Saturated
compounds are hydrocarbons in which
hydrogen and carbon have single bonds.
They are also known as Alkanes.
Examples: all alkanes like
methane,ethane,propane,butane,pentane,hex
ane,heptane,octane,nonane,decane.
Formula for alkane:- CnH2n+2
10. Unsaturated Hydrocarbons
Unsaturated Compounds : Hydrocarbons in
which hydrogen and carbon have double or
triple bonds. hydrocarbons with double
covalent bonds are alkenes and those with
triple covalent bonds are alkynes.
There is no Meth since there is no alkyne with
1 carbon atom
11. Examples And Formula Of
Unsaturated Hydrocarbon
Examples of Unsaturated Hydrocarbons:-
Alkenes- Propene, Butene, Pentene etc…
Alkynes- Propyne, Butyne, Pentyne etc…
Formula Of Alkene-CnH2n
Formula Of Alkyne- CnH2n-2
There IS No METH FOR ALKYNES
12. Chains, Branches, Rings
No Of
C
atoms
Prefixes Alkane=
Suffix:-ane
CnH2n+2
Alkene=Suffix
:-ene
CnH2n
Alkyne=Suffix
:-yne
CnH2n-2
C1 Meth CH4 -------------------- --------------------
C2 Eth C2H6 C2H4 C2H2
C3 Prop C3H8 C3H6 C3H4
C4 But C4H10 C4H8 C4H6
C5 Pent C5H12 C5H10 C5H8
C6 Hex C6H14 C6H12 C6H10
C7 Hept C7H16 C7H14 C7H12
C8 Oct C8H18 C8H16 C8H14
C9 Non C9H20 C9H18 C9H16
C10 Dec C10H22 C10H20 10H18
13. Lewis Structures
A part from branched structures, carbon
compounds are present in cyclic form.
Example: Electron Dot structure
:Lewis structures (electron dot structures)
are diagrams that show the bonding between
atoms of a molecule and the lone pairs of
electrons that may exist in the molecule.
14. Steps to draw Lewis Structure
Steps to draw a Lewis structure :
1. Decide how many valence (outer shell) electrons are
possessed by each atom in the molecule.
2.If there is more than one atom type in the molecule, put the
most metallic or least electronegative atom in the center. Recall that
electro-negativity decreases as atom moves further away from
fluorine on the periodic chart.
3.Arrange the electrons so that each atom contributes one
electron to a single bond between each atom.
4.Count the electrons around each atom: are the octets
complete? If so, your Lewis dot structure is complete.
15. Steps
5. If the octets are incomplete, and more electrons
remain to be shared, move one electron per bond
per atom to make another bond. Note that in
some structures there will be open octets
(example: the B of BF3), or atoms which have ten
electrons (example: the S of SF5)
6. Repeat steps 4 and 5 as needed until all octets
are full.
7. Redraw the dots so that electrons on any given
atom are in pairs wherever possible.
16. Homologous Series
It is a series of compounds in which the same functional group
substitutes for hydrogen in a carbon chain.
For instance, the ALCOHOLS (OH) group
The successive member differs by one -CH2 unit and 14 units of
mass.
The chemical properties are imparted by the functional group
thus all members have similar chemical properties. But the
members have different physical properties.
The physical properties vary among the members of homologous
series due to difference in their molecular mass.
Melting point and boiling point increases with increasing
molecular mass.
17. Functional Group
Functional Group Suffix Prefix
Alkene- ene
Alkyn- yne
Alcohol- ol
Aldehyde- al
Ketone- one
Carboxylic acid- oic acid
chlorine -chloro
3. If a suffix is added, then final ‘e’ is removed
from the name e.g.methanol (methane-e =
methan + ol).
Hetero Atom Functional Group Formula of Functional
group
Cl/Br
Oxygen
Halo- (Chloro/bromo)
1)Alcohol
2)Aldehyde
3)Ketone
4)Carboxylic Group
—Cl, —Br (substitutes for
hydrogen atom)
—OH
|
C=O
|
H
--c=O
|
--C=O
|
OH