1 :- what is the difference between initiator and catalyst???
Catalyst ??
Ans :-

 Catalyst  

is a substance that makes the reaction fast but recovered at the end of the reaction. It increases or decreases the rate of the reaction depending upon conditions(Pressure, Volume,Temperature, Chemicals)  provided.e.g Ni, Cd, Pd, ethylene, formaldehyde, sun light etc

Initiators  

is a substance that initiate the chemical reaction it can be a catalyst but can't be recovered at the end of reaction generally. An initiator act as catalyst when rate of reaction is desired but in general sense it is difficult to isolate the initiator at the end of the reaction.e.g Chlorine radical under sunlight

nuclear waste management

Complete uranium cycle information

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Nuclear waste types and management

All the methodologies and process is briefly discussed in this report

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Periodic Table History

                                                        -: Periodic Table Historical View :-

Initiatory :-

A necessary prerequisite to the construction of the periodic table was the discovery of the individual elements. Although elements such as gold, silver, tin, copper, lead and mercury have been known since antiquity, the first scientific discovery of an element occurred in 1649 when Hennig Brand discovered phosphorous. During the next 200 years, a vast body of knowledge concerning the properties of elements and their compounds was acquired by chemists. By 1869, a total of 63 elements had been discovered. As the number of known elements grew, scientists began to recognize patterns in properties and began to develop classification schemes.

Triads:-

In 1817 Johann Dobereiner noticed that the atomic weight of strontium fell midway between the weights of calcium and barium, elements possessing similar chemical properties. In 1829, after discovering the halogen triad composed of chlorine, bromine, and iodine and the alkali metal triad of lithium, sodium and potassium he proposed that nature contained triads of elements the middle element had properties that were an average of the other two members when ordered by the atomic weight (the Law of Triads).

First Flight Towards Designing Periodic Table :-

 De Chancourtois transcribed a list of the elements positioned on a cylinder in terms of increasing atomic weight. When the cylinder was constructed so that 16 mass units could be written on the cylinder per turn, closely related elements were lined up vertically. This led De Chancourtois to propose that "the properties of the elements are the properties of numbers." De Chancourtois was first to recognize that elemental properties reoccur every seven elements, and using this chart, he was able to predict the the stoichiometry of several metallic oxides. Unfortunately, his chart included some ions and compounds in addition to elements.

Law of Octaves:-
John Newlands, an English chemist, wrote a paper in 1863 which classified the 56 established elements into 11 groups based on similar physical properties, noting that many pairs of similar elements existed which differed by some multiple of eight in atomic weight. In 1864 Newlands published his version of the periodic table and proposed the Law of Octaves (by analogy with the seven intervals of the musical scale). This law stated that any given element will exhibit analogous behavior to the eighth element following it in the table.

Elements In Family Order:-
A year earlier (1864) Lothar Meyer published a periodic table which described the placement of 28 elements. Meyer's periodic table ordered the elements into groups arranged in order of their atomic weights. His periodic table arranged the elements into 6 families according to their valence, which was the first attempt to classify the elements according to this property.

In 1869, Lothar Meyer compiled a Periodic Table of 56 elements based on the periodicity of properties such as molar volume when arranged in order of atomic weight. Both Meyer and Mendeleev constructed periodic tables independently that are credited as being the basis of the modern table. Meyer was more impressed by the periodicity of physical properties, while Mendeleev was more interested in the chemical properties.
Mendeleev's Table Order:-

Mendeleev also published his periodic table & law in 1869, but he also forecast the properties of missing elements, and chemists began to appreciate it when, soon after, the discovery of elements predicted by gaps in his table took place.
"...if all the elements be arranged in order of their atomic weights a periodic repetition of properties is obtained."

This is known as Periodic Law and was stated by Mendleev
     The periodic law, however, appears to have been independently formulated by at least six people within one decade - De Chancourtois, Newlands, Lothar Meyer, Mendeleev, Hinrichs, and Odling. Periodic tables have always been related to the way scientists thought about the shape and structure of the atom, and the relationships between elements, so has changed accordingly over time.

1894 Ramsay isolated Argon, and in the next year discovered helium. He went on to discover neon, krypton and xenon, and added a group to the periodic table to be called the Noble Gases - elements least likely to associate with others.

Later, the table was reordered by Mosely according to atomic numbers (nuclear charge) rather than by weight, thereby modifying the Periodic Law.

The Periodic Law revealed important analogies among the 94 naturally occurring elements, and stimulated renewed interest in Inorganic Chemistry in the nineteenth century which has carried into the present with the creation of artificially produced, short lived elements of `atom smashers' and supercolliders of high energy physics.

Harry D. Hubbard, of the United States National Bureau of Standards, modernized Mendeleev's periodic table, and his first work was published in 1924. This was known as the "Periodic Chart of the Atoms".

Into the 1930s the heaviest elements were being put up in the body of the periodic table, and Glenn Seaborg "plucked those out" while working with Fermi in Chicago, naming them the Actinide series, which later permitted proper placement of subsequently 'created' elements - the Transactinides, changing the periodic table yet again. These elements were shown separate from the main body of the table.

Several scientists - and (me) a science exhibit designer - have revived the Chancourtois 3-D periodic table concept in the 20th Century. Some have started with a ribbon of elements in atomic number sequence and wrapped it in a spiral to vertically align elements with similar properties, which establishes the ‘periodic’ nature of the table. Others may have merely wrapped the plane of the flat table - after ramping the element rows – escalator-like – in the p-block - and let the post Emile/Dmitri element blocks loop to allow a perfect atomic number sequence. Some may have been seeking to resolve technical questions, and others, like Courtines, Gamov and Alexander, aiming for a better educational tool.

When Seaborg was shown the 1965 Alexander Arrangement in 1997, he said that it was 'correct', and later told a photographer that it was his 'favorite' periodic table. This arrangement retains the separate Lanthanide and Actinide series, but re-integrates them at the same time, a possibility only by using all three dimensions to produce a gap-free table.
The periodic table has been improved continuously over the last century and a half, built on the shoulders of many creative scientists.

The newer versions improve the educational possibilities by making possible element number continuity, easing both use & understanding of the immense correlative power of the periodic chart in teaching, learning, and working with chemistry.

Branches Of Chemistry

Chemistry History - Chemistry history is the branch of chemistry and history that traces the evolution over time of chemistry as a science. To some extent, alchemy is included as a topic of chemistry history.
There are many branches of chemistry or chemistry disciplines. The 5 main major branches of chemistry are considered to be organic chemistry, inorganic chemistry, analytical chemistry, physical chemistry and biochemistry.Here we define chemistry in random view branches that are known now a days
Chemical Engineering - Chemical engineering involves the practical application of chemistry to solve problems.

Agrochemistry - This branch of chemistry may also be called agricultural chemistry. It deals with the application of chemistry for agricultural production, food processing, and environmental remediation as a result of agriculture.
Analytical Chemistry - Analytical chemistry is the branch of chemistry involved with studying the properties of materials or developing tools to analyze materials.
Astrochemistry - Astrochemistry is the study of the composition and reactions of the chemical elements and molecules found in the stars and in space and of the interactions between this matter and radiation.
Biochemistry - Biochemistry is the branch of chemistry concerned with the chemical reactions that occur inside living organisms.
Cluster Chemistry - This branch of chemistry involves the study of clusters of bound atoms, intermediate in size between single molecules and bulk solids.
Combinatorial Chemistry - Combinatorial chemistry involves computer simulation of molecules and reactions between molecules.
Electrochemistry - Electrochemistry is the branch of chemistry that involves the study of chemical reactions in a solution at the interface between an ionic conductor and an electrical conductor. Electrochemistry may be considered to be the study of electron transfer, particularly within an electrolytic solution.
Environmental Chemistry - Environmental chemistry is the chemistry associated with soil, air, and water and of human impact on natural systems.
Food Chemistry - Food chemistry is the branch of chemistry associated with the chemical processes of all aspects of food. Many aspects of food chemistry rely on biochemistry, but it incorporates other disciplines as well.

General Chemistry - General chemistry examines the structure of matter and the reaction between matter and energy. It is the basis for the other branches of chemistry.
Geochemistry - Geochemistry is the study of chemical composition and chemical processes associated with the Earth and other planets.
Green Chemistry - Green chemistry is concerned with processes and products that eliminate or reduce the use or release of hazardous substances. Remediation may be considered part of green chemistry.

Inorganic Chemistry - Inorganic chemistry is the branch of chemistry that deals with the structure and interactions between inorganic compounds, which are any compounds that aren't based in carbon-hydrogen bonds.
Note:-
(Kinetics - Kinetics examines the rate at which chemical reactions occur and the factors that affect the rate of chemical processes.)

Medicinal Chemistry - Medicinal chemistry is chemistry as it applies to pharmacology and medicine.

Nanochemistry - Nanochemistry is concerned with the assembly and properties of nanoscale assemblies of atoms or molecules.

Nuclear Chemistry - Nuclear chemistry is the branch of chemistry associated with nuclear reactions and isotopes.

Organic Chemistry - This branch of chemistry deals with the chemistry of carbon and living things.

Photochemistry - Photochemistry is the branch of chemistry concerned with interactions between light and matter.

Physical Chemistry - Physical chemistry is the branch of chemistry that applies physics to the study of chemistry. Quantum mechanics and thermodyamics are examples of physical chemistry disciplines.

Polymer Chemistry - Polymer chemistry or macromolecular chemistry is the branch of chemistry the examines the structure and properties of macromolecules and polymers and finds new ways to synthesize these molecules.

Solid State Chemistry - Solid state chemistry is the branch of chemistry that is focused on the structure, properties, and chemical processes that occur in the solid phase. Much of solid state chemistry deals with the synthesis and characterization of new solid state materials.
Note:--
(Spectroscopy - Spectroscopy examines the interactions between matter and electromagnetic radiation as a function of wavelength. Spectroscopy commonly is used to detect and identify chemicals based on their spectroscopic signatures.)

Thermochemistry - Thermochemistry may be considered a type of Physical Chemistry. Thermochemistry involves the study of thermal effects of chemical reactions and the thermal energy exchange between processes.

Theoretical Chemistry - Theoretical chemistry applies chemistry and physics calculations to explain or make predictions about chemical phenomena.

Scientific procedure to obtain data

Viewed from an historical point of view, it is clear that the scientific knowledge has been obtained and that therefore science has advanced in a series of fairly logical steps. On the other hand, counterparts to these steps are difficult to identify in the day-to-day professional activities of a scientist.The way in which science and in particular chemistry advances can be describes in terms of a series of cycles (see diagram below). Observations and data (and laws) lead to the proposal of theories that, in turn, suggest predictions which can be tested by designing new experiments, and the whole process starts all over again.

Introduction Of Chemistry

At one time it was easy to define chemistry. The traditional definition goes something like this: Chemistry is the study of the nature, properties, and composition ofmatter, and how these undergo changes. That served as a perfectly adequate definition as late as the 1930s, when natural science (the systematic knowledge of nature) seemed quite clearly divisible into the physical and biological sciences, with the former being comprised of physics, chemistry, geology and astronomy and the latter consisting of botany and zoology. This classification is still used, but the emergence of important important fields to study such as oceanography, paleobotany,meteorology, pharmacy and biochemistry, for example, have made it increasingly clear that the dividing lines between the sciences are no longer at all sharp. Chemistry, for instance, now overlaps so much with geology (thus we have geochemistry), astronomy (astrochemistry), and physics (physical and analytical chemistry) that it is probably impossible to devise a really good modern definition of chemistry, except, perhaps, to fall back on the operational definition: Chemistry is what chemists do.