Chemistry AS Keywords and definitions (AQA)

Question	Answer
Covalent Bond	A shared pair of electrons
Dative Covalent bonding (Co-ordinate bonding)	Covalent bonding where one atom in the bond provides both electrons for the bond
Electronegativity	The ability of an atom to attract the electrons within a covalent bond towards itself.
van de Walls forces	Weak intermolecular forces where changing distribution of charge leads to instantaneous dipoles, which induce dipoles in nearby atoms.
Dipole-Dipole Forces (Permanent Dipoles)	Intermolecular forces caused by attraction between polar molecules (Due to a large difference
Hydrogen bonding	A type of intermolecular force in which a hydrogen atom interacts with a highly electronegative atom (N O F) with a δ- charge.
Electron pair repulsion theory (VSEPR)	Theory that governs shapes of molecules wherein e- pairs repel and spread out in order to be as far apart as possible.
Endothermic reaction	+ΔΗ Bond enthalpy of the products is greater than that of the reactants (energy taken in)
Exothermic reaction	-ΔH Bond enthalpy of products is less than that of the reactants (energy released)

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	Created by Emily Y :) about 8 years ago