DEFINITIONS Flashcards
Relative Isotopic Mass
the mass of an atom of an isotope compared with 1/12th of the mass of an atom of carbon-12.
Relative Atomic Mass
is the weighted mean mass of an atom of an element compared with 1/12th of the mass of an atom of carbon-12.
general formula
the simplest algebraic formula of a member of a homologous series
Empirical Formula
the simplest whole number ratio of atoms of each element present in a compound
molecular formula
actual number of atoms of each element in a molecule
structural formula
minimal detail that shows the arrangement of atoms in a molecule in space
Homologous Series
a series of organic compounds containing the same functional group
with successive members differing by -CH2
.
carbocation
are positively charged carbon atoms with only three covalent bonds instead of four
- primary - least stable - carbon with + charge attached to only one alkyl group
- secondary
- tertiary - most stable
radical
a species with an unpaired electron
orbital
region that can hold up to two electrons, with opposite spins
Ionic Bonding
an electrostatic attraction between positive and negative ions
Covalent bonding
the strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.
Dative covalent bond
a shared pair of electrons in which the bonded pair has been provided by one of the bonding atoms only; also called a co-ordinate bond.
Electronegativity
the attraction of a bonded atom for the pair of electrons in a covalent bond.
First ionisation energy
the energy required to remove one electron from one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions.
Metallic bonding
strong electrostatic attraction between cations and delocalised electrons.
Disproportionation
is a redox reaction in which the same element is both oxidised and reduced.
Hess’s Law
the enthalpy change for a reaction that is independent of the route taken.
heterogenous catalyst
the catalyst is in a different phase to the reactants
homogenous catalyst
the catalyst is in the same phase as the reactants
Adsorption
where something sticks to a surface
- One or more of the reactants are adsorbed on to the surface of the catalyst at active sites.
electrophile
electron pair acceptor
nucleophile
electron pair donor
Structural isomers
compounds that have the same molecular formula but different structural formulae