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Any of a subgroup of rare-earth elements, of which the cerium and terbium metals comprise the other two subgroups.

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Capillary Action

The drawing of a liquid up the inside of a small-bore tube when adhesive forces exceed cohesive forces, or the depression of the surface of the liquid when cohesive forces exceed the adhesive forces.

Charle's Law

At constant pressure the volume occupied by a definite mass of gas is directly proportional to its absolute temperature.

Lewis Dot Formula (Electron Dot Formula)

Representation of the core of a molecule, ion or formula unit by showing atomic symbols and only outer shell electrons.

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Photochemical Oxidants

Photochemically produced oxidizing agents capable of causing damage to plants and animals.

The most expensive metal in the world

Do you think the most expensive metal is gold? No! On earth there are more valuable metals. But we need to divide the value of metals that occur in nature, and metals - isotopes, which are obtained in special laboratories. Let’s look at natural metals first.

Melting Point

The temperature at which liquid and solid coexist in equilibrium, also the freezing point.

Greenhouse Effect

Trapping of heat at the surface of the earth by carbon dioxide and water vapour in the atmosphere.

Heat of Crystallization

The amount of heat that must be removed from one gram of a liquid at its freezing point to freeze it with no change in temperature.

Coordination Isomers

Isomers involving exchanges of ligands between complex cation and complex anion of the same compound.