Friday, March 9, 2012
p- block |
In p- block elements the last electron enters the outermost p orbital. As we know that the number if p- orbitals is three and therefore the maximum no of electrons that can be accommodated in a set of p orbitals is six. Consequently there are six groups of p- block elements in the periodic table numbering from 13 to 18. Boron, carbon, nitrogen, oxygen, fluorine and helium heads the groups. Their valence shell electron configuration is ns(2) np(1-6) except for helium.
Elements in p- block |
The inner core of the electronic configuration may, however, differ. The difference in the inner core of the elements greatly influences their physical properties(such as atomic and ionic radii, ionization enthalpy,etc) as well as chemical properties. A lot of variation in properties of elements in a group of p- block is observed. The maximum oxidation state shown by a p- block element is equal to the total number of the valence electrons. Clearly, the number of possible oxidation states increases towards the right of the periodic table. In addition to this so called group oxidation state, p- block elements may show other oxidation states which normally differ from the total number of valence electrons by unit of two. in Boron, Carbon and Nitrogen families the group oxidation state is most stable for the lighter elements in the group.
Friday, March 9, 2012 by Unknown · 0
Friday, February 24, 2012
All the living bodies are composed of several lifeless substances which are present in their cells in a very complex and highly organized form. These are called bio-molecules. Some common examples are carbohydrates, proteins, enzymes, nucleic acids, lipids, amino acids, fats,etc. The molecules combine in specific manner to produce life. Many of the bio-molecules are polymers. For example, starch, proteins, nucleic acids are condensation polymers of simple sugars, amino acids and nucleotides respectively.
Most of the biochemical reactions take place in dilute solutions(with pH near 7) at body temperature (nearly 37 C) and at 1 atmospheric pressure. These biochemical reactions are very complex and highly selective. Bio-molecules are related to living organisms in the following sequence :
LIVING ORGANISMS----> ORGANS----> TISSUES----> CELLS----> ORGANELLES----> BIO-MOLECULES.
The second picture represents the structure of DNA(deoxyribo nucleic Acid).
Friday, February 24, 2012 by Unknown · 0
Thursday, February 23, 2012
Facebook is one of the most popular social networking site in the modern world. It has more than a million of users. Now a days, a new trend of an empty Facebook status update has been started. Many users of Facebook post empty message on their friends walls so as to irritate them. So as I too. In this post i will show you how to put an empty Facebook status update, so that you can also start Facebook with new excitement. The tutorial to update an empty Facebook status message goes like this::-
1) Sign in to your Facebook account.
2) Click on update status.
3) Type the following code in it "@[0:0 ]" without quotes.
4) Now post it.
5) You will see your Empty Facebook Status Update.
Enjoy!!
Thursday, February 23, 2012 by Unknown · 0
Tuesday, February 21, 2012
Chemistry plays an important role in our everyday life. Since the beginning of this branch of science, it has been in the service of mankind. Our daily needs of food, clothing, shelter, potable water, medicines, etc. are in one or other manner connected with chemical compound, processes and principles.
We always owe a debt to chemists for their important contributions for giving us life saving drugs, synthetic fibers, synthetic detergents, variety of cosmetics, preservatives for our food, fertilizers, pesticides, paper, glass, strength materials, plastics, beautiful paints,etc. There is no aspect of our life that is not affected by the developments in chemistry. In fact, chemistry is the single branch of science which profoundly influences the existence of human beings and the habitat. Thus, the mankind owes much to chemistry because it has improved the quality of life.
The chemical substances used for treatment of diseases and for reducing suffering from pain are called medicines or drugs. The term chemotherapy is used for the science in which suitable chemicals are used for the treatment of diseases. These chemicals have specific effect for destroying the invading organisms without injuring the cells of the body. In the ancient practices of treatment of diseases like Ayurvedic, the Unani systems or the modern allopathic system, the drugs used are chemical compounds of natural or synthetic origin.
Tuesday, February 21, 2012 by Unknown · 0
This post confirms my ownership of the site and that this site adheres
to Google Adsense program policies and Terms and
Conditions:ca-pub-9064108103595622
to Google Adsense program policies and Terms and
Conditions:ca-pub-9064108103595622
by Unknown · 0
Subscribe to:
Posts (Atom)