Mr Ball's Flashcards
Sub shell
A group of the same type of atomic orbitals (s, p, d or f) within a cell.
Ion
A positively or negatively charge atom or (covalently bonded) group of atoms (a molecular ion).
Polar covalent bond
A bond with a permanent dipole.
Redox reaction
A reaction in which both reduction and oxidation take place.
Molar volume
The volume per mole of a gas. The units of molar volume are dm3 mol-1. At room temperature and pressure the molar volume is approximately 24.0 dm3 mol-1.
Atomic orbital
A region within an atom that can hold up to two electrons, with opposite spins.
(Successive) Ionisation energy
A measure of the energy required to remove each electron in turn, e.g. the second ionisation energy is the energy required to remove one electron from each ion in one mole of gaseous 1+ ions to form one mole of gaseous 2+ ions.
Anion.
A negatively charged ion.
Thermal decomposition
The breaking up of chemical substance with heat into at least two chemical substances.
Oxidation
Loss of electrons or an increase in oxidation number.
Oxidising agent
A reagent that oxidises (take electrons from) another species.
(Second) ionisation energy.
The energy required to remove one electron from each ion in one mole of gaseous 1+ ions to form one moles of gaseous 2+ ions.
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.
Stoichiometry
The molar relationship between the relative quantities of substances taking part in a reaction.
Intermolecular force
An attractive force between neighbouring molecules. Intermolecular forces can be van der Waals’ forces (induced dipole-dipole forces), permanent dipole-dipole forces or hydrogen bonds.
Water of crystallisation
Water molecules that form an essential part of the crystallin structure of a compound.
Electron shielding
The repulsion between electrons in different inner shells. Shielding reduces the net attractive force from the positive nucleus on the outer shell electrons.
Electronegativity
A measure of the attraction of a bonded atom for the pair of electrons in a covalent bond.
Relative molecular, Mr
The weighted mean mass of a molecule compared with one twelfth of the mass of an atom of carbon-12.
Relative formula mass
The weighted mean mass of a formula unit compared with one twelfth of the mass of an atom of carbon-12.
Coordinate bond
A shared pair of electrons which has been provided by one of the bonding atoms only; also called a dative covalent bond.
(first) ionisation energy
The energy required to remove the most loosely held electron from one mole of gases atoms.
Mole
The amount of any substance containing as many particles as there are carbon atoms in exactly 12 g of the carbon-12 isotope.
Isotopes
Atoms of the same element with different numbers of neutrons and different masses.
Concentration
The amount of solute, in mol, per 1 dm3 (1000 cm3) of solution.
Compound
A substance formed from two or more chemically bonded elements in a fixed ratio, usually shown by a chemical formula.
Giant covalent lattice
A three dimensional structure of atoms, bonded together by strong covalent bonds.
Permanent dipole
A small charge difference across a bond resulting from a difference in electro-negativities of the bonded atoms.
Precipitation reaction
The formation of a solid from a solution during a chemical reaction. Precipitates are often formed when two aqueous solutions are mixed together.
Ionic bonding
The electrostatic attraction between oppositely charged ions.
Atomic (proton) number
The number of protons in the nucleus of an atom.
Molecular formula
The number of atoms of each element in a molecule.
Empirical formula
The simplest whole number ratio of atoms of each element present in a compound.
Salt
A chemical compound formed from an acid, when a H+ ion from the acid has beed replaced by a metal ion or another positive ion, such as ammonium ion, NH4+.
Cation
A positively charged ion.
Disproportion
The oxidation and reduction of the same element in a redox reaction.
Dative covalent
A shared pair of electrons which has been provided by one of the bonding atoms only; also called coordinate bond.
Acid
A species that is a proton donor.
Amount of substance
The quantity whose unit of the mole Chemists use ‘amount of substance’ as a means of counting atoms.
Hydrogen bond
A strong dipole-dipole attraction between an electron-deficient hydrogen atom (O-H or or N-H) on one molecule and a lone pair of electrons on a highly electronegative atom on a different molecule.
Giant ionic lattice
A three dimensional structure of oppositely charged ions, bonded together by strong ionic bonds.
Relative atomic mass
The weighted mean mass of an atom of an element compared with one twelfth of the mass of an atom of carbon-12.
Period
A horizontal row of elements in the periodic table. Elements show trends in properties across a period.
Delocalised electrons
Electrons that are shared between more than two atoms.
Alkali
A type of base that dissolves in water forming hydroxide ions (OH-).
Reduction
Gain of electrons or a decrease in oxidation number.
Shell
A group of atomic orbitals with the same principal quantum number, n. Also known as a main energy level.
Standard solution
A solution of known concentration. Standard solutions are normally used in titrations to determine unknown information about a substance.
Simple molecular lattice
A three-dimensional structure of molecules, bonded together by weak intermolecular forces.
Species
Any type of particle that takes part in a chemical reaction.
Van der Waals’ forces
Very weak attractive forces between induced dipoles in neighbouring molecules.
Avogadro constant
The number of atoms per mole of the carbon-12 isotope. (6.02 x 10^23 mol-1)
Relative isotopic mass
The mass of an atom of an isotope compared with one-twelfth of the mass of an atom of carbon-12.
Covalent bond
A bond formed by a shared pair of electrons.
Electron configuration
The arrangement of electrons in an atom.
Giant metallic lattice
A three dimensional structure of positive ions and delocalised electrons, bonded together by strong metallic bonds.
Lone pair
An outer shell pair of electrons that is not involved in chemical bonding.
Metallic bond
The electrostatic attraction between positive metal ions and delocalised electrons.
Anydrous
A substance that contains no water molecules.
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 electrons shells or energy levels.
Mass (nucleon) number
The number of particles (proteins and neutrons) in the nucleus.
Molar mass, M
The mass of one mole of a substance. The units of molar mass are g mol^-1.
Periodicity
A regular periodic variation of properties of elements with atomic number and position in the periodic table.
Hydrated
Crystalline and containing water molecules.
Base
A species that is a proton acceptor.
Group
A vertical column in the periodic table. Elements in a group have similar properties and their atoms have the same number of outer shell electrons.
Reducing agent
A reagent that reduces (adds electrons to) another species.
Polar molecule
A molecule with an overall dipole, taking into account any dipoles across bonds.
Spectator ions
Ions that are present but take no part in a chemical reaction.
Permanent dipole-dipole force
An attractive force between permanent dipoles in neighbouring polar molecules.
