AQA A Level Chemistry June 2025 Paper
1 Question Paper [VERIFIED]
State the electron rules - Lowest energy filled first (3d>4s)
Line up parallel
Single until forced to pair
Electronegativity - The ability of an atom to attract electrons within a covalent bond
RAM (relative atomic mass) - Average mass of one atom compared to 1/12th the mass of a c-12 atom
-
Ionisation energy - The energy required to remove one mole of electrons from each of one mole of gaseous atoms to form one
mole of positive gaseous ions
(Endothermic)
Trends of Ionisation Energy - Across a period, i.e increases as there is no increase in shielding but an increase in atomic number
Decrease down a group due to increased shielding reducing the electrostatic force of attraction from the nucleus
Drop at 2,3 - Al - Between groups 2,3... first electron in p orbital
- increase in shielding
- reduce forces of attraction
- less energy required to remove
Drop at 4,5 - P - between groups 4-5 there is a drop
- First electron pairing
- increased repulsion
- less energy is required to remove an eleccte
Isotopes - Atoms with the same atomic number but a different mass number
- do not react differently as same electron configuration
Factors Affecting I.E - -Atomic Radius
, -Shielding
-Effective Nuclear Charge
-Proton Number
Not 100% yield because... - Incomplete Reactions
Unwanted side reactions
Products lost as gases
Ice less dense than water - Water - hydrogen bonds continuously broken and reformed
Ice - hydrogen bonds kept in a fixed position so are slightly longer
Increased distance causes ice to be less dense and float
Enthalpy - Measure of heat content of a substance under constant conditions
Endothermic reaction - Heat is given off
Negative enthalpy
Bond making - releasing energy
Combustion/ Respiration
Endothermic Reaction - Heat energy taken in
Positive Enthalpy
Bond breaking requires energy
Photosynthesis/ Thermal Decomposition
Calculating Enthalpy Change - Reactants - Products
Or
KJ^-1mol
Q=MCAT
Divided by moles
Hess's Law - Enthalpy change is independent of the route taken
1 Question Paper [VERIFIED]
State the electron rules - Lowest energy filled first (3d>4s)
Line up parallel
Single until forced to pair
Electronegativity - The ability of an atom to attract electrons within a covalent bond
RAM (relative atomic mass) - Average mass of one atom compared to 1/12th the mass of a c-12 atom
-
Ionisation energy - The energy required to remove one mole of electrons from each of one mole of gaseous atoms to form one
mole of positive gaseous ions
(Endothermic)
Trends of Ionisation Energy - Across a period, i.e increases as there is no increase in shielding but an increase in atomic number
Decrease down a group due to increased shielding reducing the electrostatic force of attraction from the nucleus
Drop at 2,3 - Al - Between groups 2,3... first electron in p orbital
- increase in shielding
- reduce forces of attraction
- less energy required to remove
Drop at 4,5 - P - between groups 4-5 there is a drop
- First electron pairing
- increased repulsion
- less energy is required to remove an eleccte
Isotopes - Atoms with the same atomic number but a different mass number
- do not react differently as same electron configuration
Factors Affecting I.E - -Atomic Radius
, -Shielding
-Effective Nuclear Charge
-Proton Number
Not 100% yield because... - Incomplete Reactions
Unwanted side reactions
Products lost as gases
Ice less dense than water - Water - hydrogen bonds continuously broken and reformed
Ice - hydrogen bonds kept in a fixed position so are slightly longer
Increased distance causes ice to be less dense and float
Enthalpy - Measure of heat content of a substance under constant conditions
Endothermic reaction - Heat is given off
Negative enthalpy
Bond making - releasing energy
Combustion/ Respiration
Endothermic Reaction - Heat energy taken in
Positive Enthalpy
Bond breaking requires energy
Photosynthesis/ Thermal Decomposition
Calculating Enthalpy Change - Reactants - Products
Or
KJ^-1mol
Q=MCAT
Divided by moles
Hess's Law - Enthalpy change is independent of the route taken
