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Numbers that describe the energies of electrons in atoms, derived from quantum mechanical treatment.

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PseudobinaryIonic Compounds

Compounds that contain more than two elements but are named like binary compounds.

Bronsted-Lowry Base

A proton acceptor

Lewis Base

Any species that can make available a share in an electron pair.

Helium

Discovered : by Sir William Ramsay in London, and independently by P.T. Cleve and N.A. Langlet in Uppsala, Sweden in 1895.
Origin : The name is derived from the Greek ‘helios’,sun.
Description :A colourless, odourless gas that is totally unreactive. It is extracted from natural gas wells, some of which contain gas that is 7% helium. It is used in deep sea diving for balloons and, as liquid helium, for low temperature research. The Earth’s atmosphere contains 5 parts per million by volume, totalling 400 million tons, but it is not worth extracting it from this source at present.
Atomic No:2 MAss No:4

Dubnium

Discovered : at both Berkeley, California, USA, and Dubna, near Moscow, Russia in 1970. Description:A highly radioactive metal which does not occur naturally, and of which only a few atoms have ever been made. It is of research interest only. Origin:The element is named after the Russian town of Dubna.

Ground State

The lowest energy state or most stable state of an atom, molecule or ion.

Law of Partial Pressures (Dalton's Law)

The total pressure exerted by a mixture of gases is the sum of the partial pressures of the individual gases.

Chemical Resources

Chemindustry.com - Includes chemicals, chemical companies, engineering, and process equipment. Search tool for products, services, and information.
Chemicals HeadQuarters - Directory of industrial chemicals and chemical products including induced and forced air coolers, halogenated compounds, distilling equipment, and foundry resins.
Chemical Advisory Service - Directories of chemical manufacturers and traders for Australia and New Zealand and chemical manufacturers for the Asia Pacific region.
Chemcompass - The database for the chemical industry. Search in over 20,000 products, 2,000 companies, brands, EINECS or CAS-numbers, and detailled company information.
Chemical Week - Daily news and product updates for professionals in the chemical industry.
American Chemistry Council News and Media - Provides chemistry business and industry news, updated issue briefs, fact sheets, press releases, media contacts and other resources.
About Chemistry - News articles, periodic tables, educational resources, newsletters, and annotated links.
General Chemistry Online - Rich resource for students and teachers of introductory chemistry. Includes interactive course guides and tutorials, an exam survival guide, reference tables, self-grading quizzes and exams, a searchable glossary, a question and answer board, answers to over 300 frequently asked questions, and a chemical trivia quiz.
Chem4Kids - Learn about chemistry including matter, atoms, and reactions. Includes online quizzes.
Chemistry & Environmental Dictionary - Contains definitions for many chemistry, environmental and other related technical terms and acronyms.
EDF Chemical Scoreboard - Toxic Release Inventory data for the US. Sources and amounts of toxic chemicals released to air and water. Also has information on health effects and other topics.
Chemistry Articles - Collection of chemistry and chemical related articles.

 

Phosphorus Oxychloride

Colorless to slightly yellow fuming liquid.

Mol. Wt.: 153.39
M.P.: 20C
B.P.: 105.1C
Density: 1.685 @ 15.5C
Vapor Pressure: 40 mm @ 27.3C
Vapor Density: 5.3
Used as the phosphorus source for phosphorus diffusion.

Percent Purity

The percent of a specified compound or element in an impure sample.