AROMATIC COMPOUNDS

                                      

STRUCTURE OF BENZENE:

Every scientist observed a very common thing that all of these elements possess approximate properties and the structure of atoms even at the subatomic level.

•      First-class: Oxygen phosphorous
•      Second class: Nitrogen Sulphur
•      Third class: carbon and silicon
•      Fourth class: it was comprised of those elements which form earthy salts which we nowadays called them “Alkaline Earth Metals”

Then, comes the contribution of Doberiener. It was also a very serious attempt to classify all the elements know to him. He also proposed the Law of Tirades.

According to this law triad Explanation:

For Example, the atomic weight of the Bromine In the Triade of halogen was the average of Chlorine and iodine. The same was true for the physical and chemical properties of that central or middle element. After that the spiral arrangement of the elements com. According to this arrangement, all the elements present on the same vertical are processed with similar chemical and physical properties.

Law of octaves:

This law is analogous to that of the law of triads. 
This law is stated as:
                                 In this context, the atomic weights of sodium are related to the eighth element f the periodic table which is Lithium. Consequently, it is astonishing that all elements in the periodic table are perfectly positioned with next element.
       Followings are the aspects of the elements in the periodic table which are always anonymous with the after element of the eighth:

•        Physical properties of the considered elements
•        Chemical properties of the considered elements
•        Isomerism of all the considered elements

 ELECTRONIC STRUCTURES OF MOLECULES:

For each molecule, an ion is a species that is possessed with only localized electrons. Electrons can be present in a bond connecting two or more atoms.

How to write Lewis Structures Of Ions: 

 Following rules operate:

1. The EXACT electrons in the molecule should be the sum of electrons ‘‘contributed’’ to the molecule or ions. Thus, for H2SO4, there are 2 (one for each hydrogen) for the sulfur)while for SO.

 For example, ethylene.

 There are a few exceptions. 

For example:

                       PCl5 and SF6 are stable compounds. In SF6,

ones and one p electron from the ground state 3s orbitals, which point to the corners of a regular octahedron.

3. It is mandatory to show the charge on each electron. The total of the  charges on ions equals the charge

ion.

ELECTRONEGATIVITY:

The electronic density that bonds the atoms is  Asymmetrical except when the two atoms are the same and have the same substituents. This attraction is

called electronegativity and it is greatest for atoms in the corner of

the periodic table.
 Thus a bond among halogens is distorted so that there is a higher probability of binding the electrons near the Fluorine than near the chlorine. Then the formula obtains the electronegativity of another from the difference between the actual energy of A--B and the mean of A--A and B--B.