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Key Definitions for AS ChemistryThe Periodic TableAmber Hornsby
Key Definitions for Unit 1 Chemistry
The Periodic Table
Displacement reaction a reaction in which a more-reactive element displaces a less-reactive element
form an aqueous solution of the latter's ions.
Disproportionation the oxidation and reduction of the same element in a redox reaction
Group vertical column in the Periodic Table. Elements in a group have similar chemical properties and
their atoms have the same number of outer-shell electrons
Metalloids elements which display properties between those of a metal and a non-metal
Period a horizontal row of elements in the Periodic Table
Periodicity a regular periodic variation of properties of elements with atomic number and position in the
Precipitation reaction the formation of a solid from a solution during a chemical reaction; precipitates
are often formed when two aqueous solutions are mixed together.
Thermal decomposition the breaking up of a chemical substance with heat into at least two chemical