Mass Number = Number of Protons +
Neutrons (in the nucleus/atom)
Relative Atomic Mass = The mean mass of
an atom of an element compared to one
twelfth the mass of a 12C atom.
The first ionisation energy is the enthalpy change when one mole of
gaseous atoms forms one mole of gaseous ions with a single positive
charge
The second ionisation energy is the enthalpy change
when one mole of gaseous ions with a single positive
charge forms one mole of gaseous ions with a double
positive charge
Ti+ (g) --> Ti2+ (g) + e-
X(g) --> X+ (g) + e-
1.The attraction of the nucleus (The more protons in the nucleus the
greater the attraction)
2. The distance of the electrons from the nucleus (The bigger the atom
the further the outer electrons are from the nucleus and the weaker the
attraction to the nucleus)
3. Shielding of the attraction of the nucleus (An electron in an outer shell is repelled by electrons in
complete inner shells, weakening the attraction of the nucleus)
Emperical Formula: the simplest whole number ratio of atoms
of each element in a compound
Covalent Bond: a shared pair of electrons
Dative Covalent Bond: A covalent bond in which the shared pair of electrons are
provided by just one of the bonded atoms
Electronegativity: The power of an atom to withdraw electron density from a
covalent bond
Structural Isomerism: Compounds which have the same
molecular formula but a different structural
formula/displayed formula
Cracking: A process used by the petroleum industry to produce shorter
alkanes and alkenes from longer alkanes
Ideal Gas Equation: pV=nRT
No. of moles = Mass/Mr
Concentration = No. of moles/Volume
Atom Economy = (mass desired product /
mass all reactants)x100
% Yield = (Actual yield / Theoretical yield)x100
Mass Spectrometry:
Step 1) Ionisation •Sample is
dissolved in a polar solvent •A
high voltage is applied to
sample •The particles lose an
electron ( or more) •Forming
positive ions with different
charges E.g. Ti Ti+ + e–
Step 2) Acceleration •Positive ions are
accelerated by an electric field •To a
constant kinetic energy
Step 3) Deflection •The positive ions with smaller m/z values will
have the same kinetic energy as those with larger m/z and will
move faster. •The heavier particles take longer to move through
the drift area. •The ions are distinguished by different flight times
Step 4) Detection •The ions reach the detector and generate a small current,
which is fed to a computer for analysis. The current is produced by electrons
transferring from the detector to the positive ions. The size of the current is
proportional to the abundance of the species