• ISOTOPES


  ATOMS OF THE SAME ELEMENT WITH DIFFERENT NUMBERS OF NEUTRONS
• ATOMIC (PROTON) NUMBER


  NUMBER OF PROTONS IN THE NUCLEUS
• MASS (NUCLEON) NUMBER


  NUMBER OF PARTICLES (PROTONS & NEUTRONS) IN THE NUCLEUS
• ION


  A POSITIVELY OR NEGATIVELY CHARGED ATOM OR (COVALENTLY BONDED) GROUP OF ATOMS
• RELATIVE ISOTOPIC MASS


  THE MASS OF AN ISOTOPE COMPARED WITH ON TWELTH OF THE MASS OF AN ATOM OFCARBON 12
• RELATIVE ATOMIC MASS


  THE WEIGHTED MEAN MASS OF AN ATOM OF AN ELEMENT COMPARED WITH ONE TWELTH OF THE MASS OF AN ATOM OF CARBON 12.
• AMOUNT OF SUBSTANCE


  THE QUANTITY OF WHOSE UNIT IS THE MOLE. CHEMISTS USE 'AMOUNT OF SUBSTANCE' AS A MEANS OF COUNTING ATOMS
• AVOGADRO CONSTANT (NA OR L)

  THE NUMBER OF ATOMS PER MOLE OF THE CARBON 12 ISOTOPES (6.02x10^23 mol^-1)
• MOLE


  THE AMOUNT OF ANY SUBSTANCE CONTAINING AS MANY PARTICLES AS THERE ARE CARBON ATOMS IN EXACTLY 12g OF THE CARBON 12 ISOTOPE
• MOLAR MASS (Mr)


  THE MASS PER MOLE OF A SUBSTANCE. THE UNITS = g mol^-1
• MOLECULE


  A SMALL GROUP OF ATOMS HELD TOGETHER BY COVALENT BONDS
• MOLAR VOLUME


  THE VOLUME PER MOLE OF A GAS. UNITS = dm^3 mol^-1. AT ROOM TEMPERATURE & PRESSURE, THE MOLAR VOLUME IS APPROXIMATELY 24.0 dm^3 mol^-1
• CONCENTRATION OF A SOLUTION

  THE AMOUNT OF SOLUTE (IN MOL) DISSOLVED PER 1dm^3 OF SOLUTION
• STANDARD SOLUTION


  A SOLUTION OF KNOWN CONCENTRATION. STANDARD SOLUTIONS ARE NORMALLY USED IN TITRATIONS TO DETERMINE UNKNOWN INFORMATION ABOUT ANOTHER SUBSTANCE.
• SPECIES


  ANY TYPE OF PARTICLE THAT TAKES PLACE IN A CHEMICAL REACTION
• STOCHIOMETRY


  THE MOLAR RELATIONSHIP BETWEEN THE RELATIVE QUANTITIES OF SUBSTANCES TAKING PART IN A REACTION
• HYDRATED


  REFERS TO A CRYSTALLINE COMPOUND CONTAINING WATER MOLECULES
• ANHYDROUS


  REFERS TO A SUBSTANCE THAT CONTAINS NO WATER MOLECULES
• WATER OF CRYSTALLISATION


  REFERS TO WATER MOLECULE THAT FORM AN ESSENTIAL PART OF THE CRYSTALLINE STRUCTURE OF A COMPOUND
• R.A.M


  (%MASS 1 + %MASS 2 + %MASS 3) / 100%
• MOLES, n


  n = m/Mr
• GAS MOLES, n


  n = V(dm3)/ 24 OR V(cm3)/24000
• CONC & VOL MOLES, n

  n = c x V (in dm3)
• IDEAL GAS EQUATION


  pV = nRT (R=8.31 J K^-1 mol^-1)
• % YIELD


  100 X (actual amount in mol of product)/(theoretical amount in mol of product)
• % ATOM ECONOMY


  100 X (molecular mass of the desired product)/(sum of molecular masses of all products)
• ACID


  PROTON DONOR
• BASE


  PROTON ACCPETOR
• ALKALI


  TYPE OF BASE THAT DISSOLVES IN WATER FORMING OH- IONS
• SALT


  ANY CHEMICAL COMPOUND FORMED FROM AN ACID WHEN A H+ ION FROM THE ACID HAS BEEN REPLACED BY A METAL ION OR ANOTHER POSITIVE ION (SUCH AS AMMONIUM NH4+)
• CATION


  POSITIVELY CHARGED ION
• ANION


  NEGATIVELY CHARGED ION
• OXIDATION NUMBER


  A MEASURE OF THE NUMBER OF ELECTRONS THAT AN ATOM USES TO BOND WITH ATOMS OF ANOTHER ELEMENT. OXIDATION NUMBERS ARE DERIVED FROM A SET OF RULES
• OXIDATION


  IS LOSS OF ELECTRONS. INCREASE IN OXIDATION NUMBER.
• REDUCTION


  GAIN OF ELECTRONS. DECREASE IN OXIDATION NUMBER.
• REDOX REACTION


  A REACTION IN WHICH BOTH REDUCTION AND OXIDATION TAKE PLACE.
• REDUCING AGENT


  REAGENT THAT REDUCES (DONATES ELECTRONS TO) ANOTHER SPECIES
• OXIDISING AGENT


  REAGENT THAT OXIDISES (ACCEPTS ELECTRONS FROM) ANOTHER SPECIES
• SHELL


  A GROUP OF ATOMIC ORBITALS WITH THE SAME PRINCIPLE QUANTUM NUMBER, n. ALSO KNOWN AS MAIN ENERGY LEVEL.
• PRINCIPAL QUANTUM NUMBER (n)

  A NUMBER REPRESENTING THE RELATIVE OVERALL ENERGY OF EACH ORBITAL, WHICH INCREASES WITH DISTANCE FROM THE NUCLEUS. THE SETS OF ORBITALS WITH THE SAME N-VALUE ARE REFERRED TO AS ELECTRON SHELLS OR ENERGY LEVELS.