Unit 1 Glossary Flashcards
absorption spectrum
a spectrum consisting of dark absorption lines superimposed on a bright continuous spectrum. It shows the absorption of radiation by a material over a range of wavelengths.
Aufbau principle
this states that orbitals are filled in order of increasing energy.
Bidentate
a ligand that contains two atoms with lone pairs of electrons capable of bonding to a metal atom or ion.
Complex
a complex consists of a central metal atom or ion surrounded by ligands.
Co-ordinate bond
a covalent bond in which one of the atoms supplies both of the electrons of the shared pair.
Co-ordination compounds
compounds in which a central metal atom or ion is attached to a group of surrounding molecules or ions by dative covalent bonds (co-ordinate bonds).
Co-ordination number
the number of nearest neighbours by which an atom or ion is surrounded in a structure.
Dative covalent bond
both the shared electrons originally came from the same atom.
Degenerate
a set of atomic orbitals that are of equal energy to each other.
Electromagnetic Spectrum
the range of frequencies or wavelengths of electromagnetic radiation.
Electronegativity
a measure of the attraction an atom involved in a bond has for the electrons of the bond.
Emission spectroscopy
the study of emission spectra produced by exited substances (often gaseous atoms or molecules).
Excitation energy
the minimum energy required to change a system from its ground state to a particular excited state.
Frequency
The number of wavelengths that pass a fixed point in one unit of time.
Ground state
the lowest possible electronic configuration the electrons in an atom can adopt.
Heisenberg’s uncertainty principle
this states that it is impossible to state precisely the position and the momentum of an electron at the same instant.
Hexadentate
a ligand that bonds to a metal ion using electron pairs on six donor atoms.
Hund’s rule
when degenerate orbitals are available, electrons fill each singly, keepings their spins parallel, before pairing starts.
Ionisation
The addition or removal of an electron to create an ion.
Ionisation energy
The energy involved in removing one mole of electrons from one mole of gaseous atoms.
Ligands
Molecules or ions that bond to the central metal atom or ion in a complex.
Lone pair
A lone or non-bonding pair of electrons is a pair of outer or valence shell electrons that have opposite spins which are not used to form covalent bonds within the molecule.
Molecular orbital
A molecular orbital is a region in space between the nuclei where there is a high probability of finding electrons. It is formed by the overlap of two atomic orbitals.
Monodentate
A ligand that bonds to a metal atom or ion using the electron pair of a single donor atom
Oxidation
The loss of electrons to form a substance. It can also be described as an increase in oxidation number.
Oxidation number
The formal charge assigned to each atom in a compound according to certain rules.
Pauli Exclusion Principle
An orbital holds a maximum of two electrons. No two electrons will have the same four quantum numbers.
Quanta
The smallest possible discrete unit of any physical property, such as energy or matter.
Reduction
The gain of electrons by a substance. It can also be described as a decrease in oxidation number.
Spectrochemical series
A list of ligands in order of the size of the crystal field splitting caused in the d orbitals.
Wavelength
The distance between adjacent crests or troughs of a wave.
Wavenumber
The reciprocal of wavelength and has the units of cm^-1
number of cycles per cm
