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The mass of one formula unit of a substance in atomic mass units.

 

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Colloid

A heterogeneous mixture in which solute-like particles do not settle out.

Delocalization

Of electrons, refers to bonding electrons that are distributed among more than two atoms that are bonded together, occurs in species that exhibit resonance.
The formation of a set of molecular orbitals that extend over more than two atoms, important in species that valence bond theory describes in terms of resonance.

Cathode Ray Tube

Closed glass tube containing a gas under low pressure, with electrodes near the ends and a luminescent screen at the end near the positive electrode, produces cathode rays when high voltage is applied.

Lone Pair

Pair of electrons residing on one atom and not shared by other atoms, unshared pair.

Amide

Compound containing the O-C-N group.Compound that can be considered a derivative of ammonia in which one or more hydrogens are replaced by a alkyl or aryl groups.

 

Coordination Number

In describing crystals, the number of nearest neighbours of an atom or ion. The number of donor atoms coordinated to a metal.

Physical Change

A change in which a substance changes from one physical state to another but no substances with different composition are formed. Example Gas to Liquid - Solid.

 

Deuterium

An isotope of hydrogen whose atoms are twice as massive as ordinary hydrogen,deuterion atoms contain both a proton and a neutron in the nucleus.

Corrosion

Oxidation of metals in the presence of air and moisture.

D-Orbitals

Beginning in the third energy level, aset of five degenerate orbitals per energy level, higher in energy than s and p orbitals of the same energy level.