Chemistry Unit 1 Definitions Flashcards
Precipitation Reaction
The formation of a solid from a solution during a chemical reaction.
Halogens
Group VII elements
Oxidising Agent
A reagent that oxidised another species.
Halides
Negative ions of group VII elements.
Electronegativity
The ability of an atom to attract a bonded pair of electrons in a covalent bond towards itself.
Disproportionation Reaction
The oxidation and reduction of the same element in a redox reaction.
Reducing Agent
A reagent that reduces another species.
Displacement Reaction
A reaction in which a more reactive element displaces a less reactive element from an aqueous solution in the latter’s ions.
Reducing Agent
A species that causes reduction in another species, whilst itself is being oxidised.
Oxidising Agent
A species that causes oxidation in another species, whilst itself is being reduced.
Reduction
Gain of electrons or a decrease in oxidation number.
Thermal Decomposition
The breaking up of a chemical substance with heat into at least two chemical substances.
Oxidation Number or Oxidation State
A measure of the number of electrons that an atom uses to bond with atoms of another element.
Redox Reaction
A reaction where both oxidation and reduction takes place.
Oxidation
Loss of electrons or an increase in oxidation numbers.
First Ionisation Energy
The minimum amount of energy required to remove one electron from each atom in one one mole of gaseous atoms to form 1+ ions.
Second Ionisation Energy
The minimum amount of energy required to remove one electron from each ion in one mole of gaseous 1+ ions to form 2+ ions.
Periodicity
Repeating patterns of properties across a period.
Electronegativity
The ability of an atom to attract a bonded pair of electrons in a covalent bond towards itself.
Alkali
A type of base that dissolves in water forming hydroxide (OH-)(aq) ions
Hydrated
The compound in question contains water.
Salt
A chemical compound formed from an acid, when a H+ ion from the acid has been replaced by a metal ion or another positive ion, such as ammonium ion NH4+.
Base
A species that is a proton ( H+) acceptor.
Anhydrous
The compound on question contains no water.
Water Of Crystallisation
Water molecules that form an essential part of the crystalline structure of a compound.
Acid
A species that is a proton ( H + ) donor.
Hydrogen Bonding
A strong dipole- dipole attraction between an electron-deficient hydrogen atom on one molecule and a lone pair of electrons
Dipole- Dipole Interactions (permanent dipole)
An attractive force between permanent dipoles in neighbouring polar molecules.
Metallic Bond
The electrostatic attraction between positive meta ions and delocalised electrons.
Ionic Bond
The electrostatic attraction between oppositely charged ions.
Coordinate Bond
A shared pair of electrons which has been provided by one of the bonding atoms only.
Van Der Waals Forces
Very weak attractive forces between induced dipoles in neighbouring molecules.w
Electronegativity
A measure of the attraction of a bonded atom for the pair of electrons in a covalent bond.
Covalent Bond
A bond formed by a shared paired of electrons.
Molecular Formula
The number of atoms of each element in a molecule.
Molar Mass
The mass per mole of a substance.
Amount Of Substance
The quantity whose unit is the mole
Mole
The amount of any substance containing as many particles as there are carbon atoms in exactly 12g of the carbon-12 isotope.
Avagadro’s Constant
The number of atoms per mole of the carbon 12 isotope.
Empirical Formula
The simplest whole-number ratio of atoms Of each element present in a compound.
Relative Isotopic Mass
The mass of an atom of an isotope compared to 1/12th the average mass of an atom of carbon-12.
Relative Atomic Mass
The average mass of an atom of an element compared to 1/12th the average mass of an element of carbon-12.
Second Ionisation Energy
The minimum amount of energy required to remove one electron from each ion in one mole of gaseous atoms to form 2+ ions.
First Ionisation Energy
The minimum amount of energy required to remove one electron from each atom in one mole of gaseous atoms to produce 1+ ion.
Atomic Number
The number of protons in the nucleus.
Isotope
Atoms of an element with different number of neutrons.
Relative Formula Mass
The average mass of a formula of a compound compared to 1/12th the average mass of an atom of carbon-12.
Relative Molecular Mass
The average mass of a molecule compared to 1/12th the mass of an atom of carbon-12.
Atomic Orbital
The region within an atom that can hold up to 2 electrons with opposite spins.
Mass Number
The number of protons and neutrons in the nucleus.
