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A fairly strong dipole-dipole interaction (but still considerably weaker than the covalent or ionic bonds) between molecules containing hydrogen directly bonded to a small, highly electronegative atom, such as N, O, or F.

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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.

Eluate

Solvent (or mobile phase) which passes through a chromatographic column and removes the sample components from the stationary phase.

Alcohol

Hydrocarbon derivative containing an --OH group attached to a carbon atom not in an aromatic ring. Alcohols are a class of organic compounds containing the hydroxyl group, OH, attached to a carbon atom.

Electrophoresis

A technique for separation of ions by rate and direction of migration in an electric field.

How is colored crystal made?

However, not everyone knows that in addition to the traditional transparent, there is still an unusually beautiful and spectacular colored crystal, which is obtained through the addition of various metal oxides into the glass. They give the crystal unusually noble shades of red, purple, blue, green and pink colors.

Hund's Rule

All orbitals of a given sublevel must be occupied by single electrons before pairing begins.

Geiger counter

A gas filled tube which discharges electriaclly when ionizing radiation passes through it.

Valence Bond Theory

Assumes that covalent bonds are formed when atomic orbitals on different atoms overlap and the electrons are shared.

Semipermable Membrane

A thin partition between two solutions through which certain molecules can pass but others cannot.

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.