Chemical Changes and Structures Flashcards
bonding electrons
shared pairs of electrons from both atoms forming the covalent bond
chemical bonding
the mechanism by which atoms are held together
chemical structure
the way in which atoms, ions or molecules are arranged
covalent bond
formed when two atoms share electrons in their outer shell to complete the filling of that shell
covalent radius
half the distance between the nuclei of two bonded atoms of an element
delocalised
electrons in metallic bonding which are free from attachement to any one metal ion and are shared amongst the entire structure
diatomic
moelcules with exactly two atoms
dipole
an atom or molecule in which a concentration of positive charges is separated from a concentration of negative charges
electronegativity
a measure of the attraction that an atom involved in a bond has for the electrons of the bond
fullerene
molecules of carbon constructed of 5- and 6- membered rings combined into hollow spherical structures
hydrogen bonds
intermolecular forces between molecules containing a hydrogen atom bonded to an atom of a strongly electronegative element such as fluorine, oxygen or nitrogen, and a highly electronegative atom on a neighbouring molecule
intermolecular forces
are those which attract atoms and molecules together (also known as van der Waals forces)
ion-electron equation
a half-equation, either oxidation or reduction, which in combination with the opposite type, can be part of a complete redox equation
ionic bond
a bond between atoms with substantially different electronegativity, which results in the formation of positive and negative ions (with the negative ion having the higher electronegativity)
ionisation energy
the energy required to remove one mole of electrons from one mole of atoms in the gaseous state
isoelectronic
having the same number of electrons
lattice
a regular 3D arrangement of particles in space
London dispersion forces
the forces of attraction which result from the electrostatic attraction between temporary and induced dipoles caused by movement of electrons in atoms and molecules
miscible
fluids which mix or dissolve in each other in all propotions
non-polar / pure covalent bond
bond between atoms with the same or very similar electronegativity which results in an equal sharing of the bonding electrons between the atoms
oxidation
a loss of electrons by a reactant in any reaction
oxidising agent
a substance which accepts electrons
periodicity
the regular recurrence of similar properties when the elements are arranged in order of increasing atomic number
permanent dipole to permanent dipole interactions
intermolcular forces of attraction which exist between polar molecules
polar covalent bond
a bond between atoms of different electronegativity, which results in an uneven distribution of electrons and a partial charge along the bond
properties
the physical and chemical characteristics of a substance
reducing agent
a substance which donates electrons
reduction
a gain of electrons by a reactant in any reaction
viscosity
the resistance to flow that is exhibited by liquids
screening/shielding effect
describes how the inner electrons reduce the attraction between the nuclear charge and bonding electrons
bonding continuum
the spectrum of bonding from pure covalent to ionic
monatomic
single, unattached atoms which are stable due to full outer energy levels
like dissolves like
a general rule about solubility, since polar molecules dissolve in polar solvents, and non-polar molecules dissolve in non-polar solvents
