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No two electrons in the same atom may have identical sets of four quantum numbers.

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Zinc

Discovered: known in India and China before 1500 and to the Greeks and Romans before 20 BC as the copper-zinc alloy brass
Origin: The name is derived from the German ‘Zink’.
Atomic no: 30
Mass No: 65
Description: A grey metal with a blue tinge. World production exceeds 7 million tons a year, and it is used to galvanise iron to prevent it rusting. It is also employed in alloys and batteries, and as zinc oxide to stabilise rubber and plastics. Zinc is essential for all living things, and is important for growth and development. The average human body contains about 2.5 grams and takes in about 15 milligrams per day. Some foods have above average levels of zinc, including herring, beef, lamb, sunflower seeds and cheese.

Alkaline Battery

A dry cell in which the electrolyte contains KOH.

Donor Atom

A ligand atom whose electrons are shared with a Lewis acid.

Autoionization

An ionization reaction between identical molecules.

Buffer Solution

Solution that resists change in pH, contains either a weak acid and a soluble ionic salt of the acid or a weak base and a soluble ionic salt of the base.

Valence Shell Electron Pair Repulsion Theory

Assumes that electron pairs are arranged around the central element of a molecule or polyatomic ion so that there is maximum separation (and minimum repulsion) among regions of high electron density.

 

Mass Action Expression

For a reversible reaction, aA + bB cC + dD the product of the concentrations of the products (species on the right), each raised to the power that corresponds to its coefficient in the balanced chemical equation, divided by the product of the concentrations of reactants (species on the left), each raised to the power that corresponds to its coefficient in the balanced chemical equation. At equilibrium the mass action expression is equal to K, at other times it is Q.[C]c[D]d [A]a[B]b = Q, or at equilibrium K.

Half-Life

The time required for half of a reactant to be converted into product(s). The time required for half of a given sample to undergo radioactive decay.

Heat

A form of energy that flows between two samples of matter because of their differences in temperature.

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.