2/1/26, 7:43 PM AQA A Level Chemistry : Dictionary
AQA A Level Chemistry : Dictionary TEST BANK EXAM
LATEST WITH ACTUAL QUESTIONS AND CORRECT
VERIFIED ANSWERS ALREADY GRADED A+ 100%
GUARANTEED PASS LATEST UPDATE-University of Glasgow
Average mass of its atoms compared to 1/12th the mass of a carbon-12
atom
Relative Atomic Mass
1. Decreases
2. Shielding is constant
3. Surface charge density is increasing
Atomic radius across a period
1. Increases
2. Shielding increases
3. Lower surface charge density
Atomic radius down a group
Strong electrostatic forces of attraction between cations and the sea of
delocalised electrons flowing through the metallic lattice.
Metallic bonding
/ 1/27
,2/1/26, 7:43 PM AQA A Level Chemistry : Dictionary
the average mass of one molecule of the substance compared to 1/12th of
a carbon-12 atom
Relative molecular mass
Simplest whole number ratio of atoms of each element in a compound
Empirical Formula
The actual number of atoms of each element in a compound
Molecular formula
The amount of energy needed to remove one mole of electrons from one
mole of a gas, to produce one mole of gaseous 1+ ions
First ionisation energy
The amount of energy needed to remove one mole of electrons from one
mole of gaseous, 1+ ions, to produce one mole of gaseous 2+ ions.
Second Ionisation energy
/ 2/27
, 2/1/26, 7:43 PM AQA A Level Chemistry : Dictionary
The ability of an atom to attract the bonding pair of electrons in a covalent
bond
Electronegativity
Enthalpy change when 1 mole of a substance is completely burned in
oxygen under standard conditions, all reactants and products being in
their standard states.
Standard Enthalpy of Combustion (R-P) (If you are given combustion
data to work out formation, ISE THE COMBUSTION FORMULA)
Enthalpy change when 1 mole of a compound is formed from its elements
under standard conditions, all reactants and products being in their
standard state.
Standard Enthalpy of Formation (P-R) (If you are given formation data to
calculate combustion, USE THE FORMATION EQUATION)
The Enthalpy Change needed to overcome 1 mole of bonds in a gaseous
state averaged over different molecules.
Mean Bond Enthalpy
1. The mean is an average of the bond enthalpy taken over many different
compounds.
Suggest a reason why the value calculated differs from the mean Xe-F
bond enthalpy. (1)
/ 3/27
AQA A Level Chemistry : Dictionary TEST BANK EXAM
LATEST WITH ACTUAL QUESTIONS AND CORRECT
VERIFIED ANSWERS ALREADY GRADED A+ 100%
GUARANTEED PASS LATEST UPDATE-University of Glasgow
Average mass of its atoms compared to 1/12th the mass of a carbon-12
atom
Relative Atomic Mass
1. Decreases
2. Shielding is constant
3. Surface charge density is increasing
Atomic radius across a period
1. Increases
2. Shielding increases
3. Lower surface charge density
Atomic radius down a group
Strong electrostatic forces of attraction between cations and the sea of
delocalised electrons flowing through the metallic lattice.
Metallic bonding
/ 1/27
,2/1/26, 7:43 PM AQA A Level Chemistry : Dictionary
the average mass of one molecule of the substance compared to 1/12th of
a carbon-12 atom
Relative molecular mass
Simplest whole number ratio of atoms of each element in a compound
Empirical Formula
The actual number of atoms of each element in a compound
Molecular formula
The amount of energy needed to remove one mole of electrons from one
mole of a gas, to produce one mole of gaseous 1+ ions
First ionisation energy
The amount of energy needed to remove one mole of electrons from one
mole of gaseous, 1+ ions, to produce one mole of gaseous 2+ ions.
Second Ionisation energy
/ 2/27
, 2/1/26, 7:43 PM AQA A Level Chemistry : Dictionary
The ability of an atom to attract the bonding pair of electrons in a covalent
bond
Electronegativity
Enthalpy change when 1 mole of a substance is completely burned in
oxygen under standard conditions, all reactants and products being in
their standard states.
Standard Enthalpy of Combustion (R-P) (If you are given combustion
data to work out formation, ISE THE COMBUSTION FORMULA)
Enthalpy change when 1 mole of a compound is formed from its elements
under standard conditions, all reactants and products being in their
standard state.
Standard Enthalpy of Formation (P-R) (If you are given formation data to
calculate combustion, USE THE FORMATION EQUATION)
The Enthalpy Change needed to overcome 1 mole of bonds in a gaseous
state averaged over different molecules.
Mean Bond Enthalpy
1. The mean is an average of the bond enthalpy taken over many different
compounds.
Suggest a reason why the value calculated differs from the mean Xe-F
bond enthalpy. (1)
/ 3/27
