unit 1:chemical changes and structure Flashcards
shared pairs of electrons from both atoms forming the covalent bond
bonding electrons
the term used to describe the mechanism by which atoms are held together
chemical bonding
what describes the way in which atoms , ions or molecules are arranged
chemical structure
what is formed when two atoms share electrons in their outer shell to complete the filling of that shell
covalent bond
the term used to describe half the distance between the nuclei of two bonded atoms of an element
covalent radius
used to describe electrons , in metallic bonding , that are free from attachment to any one metal ion and are shared amongst the entire structure
delocalised
7 molecules with only two atoms e.g. N2 , O2 , F2 , Cl2 , Br2 , I2 , H2
diatomic
an atom or molecule in which a concentration of positive charges is separated from a concentration of negative charge
dipole
a measure of the attraction that an atom involved in a bond has for the electrons of the bond
electronegativity
molecules of pure carbon constructed from 5- and 6- members rings combined into hollow structures. The most stable contains 60 carbon atoms in a shape resembling a football
fullerenes
the strongest intermolecular force , contain a hydrogen atom bonded to and atom of stingily electronegative element such as fluorine , oxygen or nitrogen , and a highly electronegative atom on a neighbouring molecule
hydrogen bonds
the term given to those which attract atoms and molecules together. they are weaker than chemical bonds. also known as van service Waals forces.
intermolecular forces
a half equation , either an oxidation or a reductions , which in combination of the opposite type , can be part of a complete redox equation
ion-electron equations
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)
ionic bond
the energy required to remove one mole of electrons from one mole of the atoms in the gaseous state
ionisation energy
this means having the same arrangement of electrons. for example the noble gas neon , a sodium ion (Na+) and a magnesium ion (Mg2+)
isoelectronic
a regular 3D arrangement of particles in space. the term is applied to metal ions in a solid , and to positive and negative ions in an ionic solid
lattice
the forces of attraction which result from the electrostatic attraction between temporary dipoles and induced dipoles caused by movement of electrons in atoms and molecules
london dispersion forces (LDF’s)
are fluids which mix or dissolve in each other in all proportions
miscible
a covalent bond between atoms with the same or very similar electronegativity, which results in an equal sharing of the bonding electrons between the atoms
non-polar (or pure) covalent bond
a loss of electrons by a reactant in any reaction
oxidation
a substance which accepts electrons
oxidising agent
the regular recurrence of similar properties when the elements are arranged in order of increasing atomic number
periodicity
additional intermolecular forces of attraction which exist between polar molecules. stronger than LDF’s for molecules with similar numbers of electrons
permanent dipole to permanent dipole interactions (PD-PD interactions)
