Abegg, Richard

 (1869-1910) German physical chemist Abegg was born in the German port of Danzig (now Gdańsk in Poland); he studied chemistry at Kiel, Tübingen, and Berlin. He graduated in 1891 as a pupil of Wilhelm Hofmann. Initially an organic chemist, he was attracted by the advances being made in physical chemistry, and in 1894 moved to Göttingen as an assistant to Hermann Nernst. Here, he worked on electrochemical and related problems.


proton donors that yield hydronium ions in water solution, or electron-pair acceptors that combine with electron-pair donors or bases; having a pH value of less than 7.


Any of a group of hydrocarbons that have carbon atoms in chains linked by single bonds and that have the general formula CnH2n+2. Alkanes can be either gaseous, liquid, or solid. They occur naturally in petroleum and natural gas, and include methane, propane and butane.


any of numerous unsaturated hydrocarbons having one double bond ; any of a series of open-chain hydrocarbons CnH2n (as ethylene


any of a series of open-chain hydrocarbons CnH2n−2 (as acetylene) having one triple bond
Alpha particles

a positively charged nuclear particle identical with the nucleus of a helium atom that consists of two protons and two neutrons and is ejected at high speed in certain radioactive transformations


the positive terminal of an electrolytic cell

Atomic mass The mass of an atom, usually expressed in atomic mass units.
Atomic particles Chemistry is concerned with the structure of atom only in terms of the three atomic particles (It is now known that these atomic particles are themselves composed of sub-atomic particles
Atomic theory any of several theories describing the structure, behavior, and other properties of the atom and its component parts
Atomic weight The average mass of an atom of an element, usually expressed relative to the mass of carbon 12, which is assigned 12 atomic mass units.
Atom the smallest component of an element having the chemical properties of the element
Avogadro, Amedeo (1776-1856)  Italian chemist and physicist who formulated the hypothesis known as Avogadro's law in 1811.


Base a compound that reacts with an acid to form a salt, as ammonia, calcium hydroxide, or certain nitrogen-containing organic compounds; a group or molecule that takes up or accepts protons
Berzelius, Jon Jacob  (1779-1848) The Swedish chemist) was one of the first European scientists to accept John Dalton's atomic theory and to recognize the need for a new system of chemical symbols.
Biological carbon refers to carbon that is generated by something living, organic
Black, Joseph (1728-1799) British chemist who rediscovered carbon dioxide (1756) and formulated the concepts of latent heat and specific heat.
Bohr, Niels (1885-1962) best known for the investigations of atomic structure and also for work on radiation, which won him the 1922 Nobel
Bonding The atoms are joined by chemical bonds which are forces of attraction that hold atoms together


Carlisle, Anthony  (1768-1842) English surgeon, in 1800 he and William Nicholson discovered electrolysis by passing a voltaic current through water, decomposing it into its constituent elements of hydrogen and oxygen
Cathode the positive terminal of a voltaic cell or battery
Cavendish, Henry  (1731-1810) British chemist and physicist who discovered the properties of hydrogen and established that water is a compound of hydrogen and oxygen
Chadwick, James  (1891-1974) English physicist: discoverer of the neutron; Nobel prize 1935
Chemical bond Any of several forces or mechanisms, especially the ionic bond, covalent bond, and metallic bond, by which atoms or ions are bound in a molecule or crystal.
Chemical compound a substance formed by chemical union of two or more elements or ingredients in definite proportion by weight
Chemical formula a representation of a substance using symbols for its constituent elements
Conservation of mass

the principle that in any closed system subjected to no external forces, the mass is constant irrespective of its changes in form; the principle that matter cannot be created or destroyed

Corpuscle a term that was originally used to describe small atomic particles, later disused in physics and chemistry, but still used in the biological field
Couper, Archibald Scott developed the theory of chemical structure, namely that tetravalent carbon atoms can link together to form large molecules, and that the bonding order of the atoms can be determined
Covalent Of or relating to a chemical bond characterized by one or more pairs of shared electrons


Dalton, John (1766-1844) British chemist whose pioneer work on the properties of gases led to his formulation of the atomic theory. He also studied his own condition of colorblindness
De Broglie, Louis  (1892-1987) French physicist and Nobel Prize Winner best known for wave-particle duality. He laid out the converse idea of Einstein's that a wave is a particle. According to de Broglie, a particle is a wave. He was awarded the 1929 Nobel Prize for physics.
De Lavoisier, Antoine-Laurent (1743-1794) French intellectual and nobleman, widely regarded as the founder of modern chemistry
Democritus Greek philosopher who developed one of the first atomist theories of the universe and espoused the doctrine that pleasure, along with self-control, is the goal of human life
Distilled water water from which impurities, as dissolved salts and colloidal particles, have been removed by one or more processes of distillation; chemically pure water.
Double bond a chemical linkage consisting of two covalent bonds between two atoms of a molecule, represented in chemical formulas by two lines, two dots, or four dots, as CH2=CH2; CH2:CH2; CH2::CH2


Electrochemistry the branch of chemistry that deals with the chemical changes produced by electricity and the production of electricity by chemical changes
Electrolysis the passage of an electric current through an electrolyte with subsequent migration of positively and negatively charged ions to the negative and positive electrodes
Electrolyte any substance that dissociates into ions when dissolved in a suitable medium or melted and thus forms a conductor of electricity
Electromagnetism the phenomena associated with electric and magnetic fields and their interactions with each other and with electric charges and currents.
Electron an elementary particle that is a fundamental constituent of matter, having a negative charge of 1.602 × 10−19 coulombs, a mass of 9.108 × 10−31 kilograms, and spin of 1/2 , and existing independently or as the component outside the nucleus of an atom.
Electron diffraction instrument a modern instrument that uses electrons to see an image
Electron dot system common compounds can be visualized by using dots as the electrons in the outer valence
Electronegative charge a charge on the nucleus of an element
Electroplate to plate or coat with a metal by electrolysis
Elements one of a class of substances that cannot be separated into simpler substances by chemical means


Fractional distillation the separation of volatile components of different boiling points in a mixture by the gradual increase of temperature and the separate collection of each component
Frankland, E. (1825-1899) English chemist, one of the foremost of his day.  He was an expert in water quality and analysis, and originated the concept of combining power, or valence, in chemistry.


Gay-Lussac, Joseph (1778-1850) French chemist and physicist known for his studies on the physical properties of gases.
Greece (ancient) refers to the period of Greek history lasting from the Greek Dark Ages ca. 1100 BC and the Dorian invasion, to 146 BC and the Roman conquest of Greece after the battle of Corinth.


Heisenberg, Werner (1901-1976) was a German theoretical physicist. He made contributions to quantum mechanics, nuclear physics, quantum field theory, and particle physics
Hooke, Robert (1635-1645) English physicist, inventor, and mathematician who contributed to many aspects of science. With Robert Boyle he demonstrated that both combustion and respiration require air and that sound does not travel in a vacuum. Hooke studied plants and other objects under microscopes and was the first to use the word cell to describe the patterns he observed. He also identified fossils as a record of changes among organisms on the planet throughout history
Hydrocarbon contain hydrogen and carbon in different proportions; carbon is derived from organic processes
Hydrogen bond a type of chemical bond in which a hydrogen atom that has a covalent link with one of the electronegative atoms (F, N, O) forms an electrostatic link with another electronegative atom in the same or another molecule


India (ancient) prior to 100 BC
Indivisible unable to divide into smaller particles
Ionic a type of chemical bonding that one element gives up electrons to another element



Kekule, August (1829-1896) German organic chemist, he was the principal founder of the theory of chemical structure
Kossel, Walther (1888-1956) German physicist known for his theory of the chemical bond (ionic bond/octet rule)


Langmuir,  Irving  (1881-1957) a physicist and chemist who developed the modern surface chemistry and the theory of adsorption catalysis
Lewis, Gilbert Newton (1875-1946) physical chemist known for the discovery of the covalent bond
Lomonosov, Mikhail ( 1711-1765) Russian polymath, scientist and writer, who made important contributions to literature, education, and science


Metallic bond the type of chemical bond between atoms in a metallic element, formed by the valence electrons moving freely through the metal lattice
Meteorology the science dealing with the atmosphere and its phenomena, including weather and climate.
Molecule the smallest physical unit of an element or compound, consisting of one or more like atoms in an element and two or more different atoms in a compound


Nasir al-Din al Tusi (1201-1274) an Islamic astronomer and mathematician who joined the Mongols who conquered Baghdad. He made important contributions to astronomy and wrote many commentaries on Greek texts
Negative charge having a surplus of electrons; having a lower electric potential 
Neutron an elementary particle having no charge, mass slightly greater than that of a proton.
Nicholson, William (1753-1815) a renowned English chemist who was also a writer on natural philosophy and chemistry as well as a translator, journalist, publisher, scientist, and inventor
Nucleus the positively charged mass within an atom, composed of neutrons and protons, and possessing most of the mass but occupying only a small fraction of the volume of the atom


Olefins Any of a class of unsaturated open-chain hydrocarbons such as ethylene, having the general formula CnH2n; an alkene with only one carbon-carbon double bond
Orbital a wave function describing the state of a single electron in an atom or in a molecule
Organic chemistry the branch of chemistry, originally limited to substances found only in living organisms, dealing with the compounds of carbon
Oxidation reaction A half-reaction in which a chemical species decreases its reduction number, usually by losing electrons


Pauling, Linus (1901-1994) one  of the first scientists to work in the fields of quantum chemistry, molecular biology and orthomolecular medicine. He is one of a small number of individuals to have been awarded more than one Nobel Prize
Petroleum products useful materials derived from crude oil (petroleum) as it is processed in oil refineries
Philosopher a person who offers views or theories on profound questions in ethics, metaphysics, logic, and other related fields
Polyethylene a plastic polymer of ethylene used chiefly for containers, electrical insulation, and packaging.
Positive charge having a deficiency of electrons; having a higher electric potential
Priestly, Joseph

 (1733-1804) best known for his experiments with gases especially that which we now call oxygen, he was extraordinarily prolific in his writings on other areas of intellectual endeavors


a positively charged elementary particle that is a fundamental constituent of all atomic nuclei.


Quantum theory any theory that treats certain phenomena by the methods of quantum mechanics


Reduction reaction A half-reaction in which a chemical species decreases its oxidation number, usually by gaining electrons
Relativity a theory, formulated essentially by Albert Einstein, that all motion must be defined relative to a frame of reference and that space and time are relative, rather than absolute concepts
Rey, Jean (1583-1645) French doctor who worked in alchemy
Rome (ancient) a civilization that grew out of a small agricultural community founded on the Italian Peninsula as early as the 10th century BC. Located along the Mediterranean Sea, it became one of the largest empires in history
Rutherford, Ernest  (1871-1937) English physicist, born in New Zealand: Nobel prize for chemistry 1908.


Schrodinger, Erwin  (1887-1961) made important contributions to the development of Quantum Mechanics and received a Nobel prize in 1933
Single bond  a chemical linkage consisting of one covalent bond between two atoms of a molecule, represented in chemical formulas by one line or two vertical dots, as C–H or C:H.
Standard Model  (physics) of particle physics is a theory that describes three of the four known fundamental interactions
Stoney, G. Johnstone  (1826-1911) best known for his introduction of the term ‘electron’ into science
Subatomic particles Any of various units of matter below the size of an atom, including the elementary particles and hadrons.


Tetravalent having a valence of four
Theorist a person who deals mainly with the theory of a subject: a theorist in medical research
Thomson, J.J. (1856-1940) discovered the electron
Triple bond a chemical linkage consisting of three covalent bonds between two atoms of a molecule, represented in chemical formulas by three lines or six dots, as CHCH or CH⋮⋮CH.


Uncertainty principle the principle of quantum mechanics, formulated by Heisenberg, that the accurate measurement of one of two related, observable quantities, as position and momentum or energy and time, produces uncertainties in the measurement of the other, such that the product of the uncertainties of both quantities is equal to or greater than h/2π, where h equals Planck's constant
Unifying theory The urge to discover a fundamental theory underlying all natural phenomena has been expressed since the beginning of civilization


Valence the relative combining capacity of an atom or group compared with that of the standard hydrogen atom. The chloride ion, Cl–, with a valence of one, has the capacity to unite with one atom of hydrogen or its equivalent, as in HCl or NaCl
Valence shell an electron of an atom, located in the outermost shell (valence shell) of the atom, that can be transferred to or shared with another atom.
Van der Waals force A weak attractive force between atoms or nonpolar molecules caused by a temporary change in dipole moment arising from a brief shift of orbital electrons to one side of one atom or molecule, creating a similar shift in adjacent atoms or molecules
Van der Waals, Johannes D. Dutch scientist and thermodynamicist famous for his work on the equation of state for gases and liquids which describe the relation between the pressure, volume, and temperature of fluids
Volta, Alessandro (1745-1827) Italian physicist who in 1800 invented the voltaic pile, which was the first source of continuous electric current
Von Humboldt, Alexander  (1769-1859) was a German naturalist, geologist and explorer