A-Level Chemistry Paper 1 Definitions Questions and Answers correct

A-Level Chemistry Paper 1 Definitions Questions and Answers correct Ionic bonding The electrostatic attraction between positive and negative ions Covalent bonding The strong electrostatic force of attraction between a shared pair of electrons and the nuclei of the bonded atoms Dative bonding Where the shared pair of electrons is supplied by one of the atoms only Electronegativity The ability of an atom to attract the bonding electrons in a covalent bond Hydrogen bonding The attraction between the lone pair on the electronegative atom and they hydrogen atom on a different molecule Metallic bonding The strong electrostatic force of attraction between cations and delocalised electrons Oxidation number Can be thought of as the number of electrons involved in bonding Acid A species that will release hydrogen atoms in aqueous solutions Base A compound that neutralises an acid to form a salt Alkali A base that dissolves in water to release hydroxide ions in aqueous solution Displacement reaction When an atom or group of atoms is replaced by a more reactive atom or group of atoms Colorimetry Measures the intensity of light passing through a sample Half life The time taken for the reactant's concentration to decrease by half Enthalpy a measure of heat energy in a chemical system Average bond enthalpy the energy required to break one mole of a specific type of bond in a gaseous molecule Enthalpy change of reaction the enthalpy change that accompanies molar quantities shown in the chemical equation, it refers to a specific equation Enthalpy change of formation The enthalpy change when one mole of a compound is formed from its elements under standard conditions Enthalpy change of combustion The enthalpy change when one mole of a substance reacts completely with oxygen under standard conditions with all reactants and products in their standard states Lattice enthalpy The enthalpy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions Enthalpy change of atomisation The enthalpy change that takes place for the formation of one mole of gaseous atoms from the element in its standard state under standard conditions First electron affinity The enthalpy change that takes place when one electron is added to each atom in one mole of gaseous atoms to form one mole of 1- ions Enthalpy of solution The enthalpy change that takes place when one mole of a solute dissolves in a solvent Enthalpy of hydration The energy change that accompanies the dissolving of gaseous ions in water to form one mole of aqueous ions Entropy The dispersal of energy within a chemical system Standard electrode potential of a half cell The emf of a half-cell connected to a standard hydrogen half-cell under standard conditions Transition metal D block elements that have an ion with an incomplete d-subshell