Terminology Flashcards
(20 cards)
Activated complex
An unstable arrangement of atoms formed at the maximum of the potential energy barrier
Activation energy
The energy required by colliding molecules to form an activated complex
Bonding continuum
A concept applied to bonding. Ionic and covalent are at opposite ends with polar covalent in between.
Catalyst
A substance which speeds up a reaction without being used up itself. It also lowers the activation energy.
Collision geometry
A term used to describe the way reactants collide with each other.
Collision theory
A theory used to explain the factors which lead to a successful reaction. The theory requires reactants to collide, the correct collision geometry and have the minimum energy (activation energy) before a reaction occurs.
Covalent atomic radius
Measure of atomic size. Half the distance between the nuclei of two covalently bonded atoms of an element.
Covalent bonding
The bond formed between two atoms who share the same electrons. Usually between two non metal atoms.
Covalent network
A very strong and stable structure formed by strong covalent bonds. All solid at room temperature and have very high melting and boiling points.
Examples; Boron, Silicon, Carbon Diamond and Carbon Graphite.
Electronegativity
The strength of the attraction by an atom of an element for its bonding electrons.
Hydrogen bonds
The molecules must contain highly polar bonds in which hydrogen atoms are linked to very electronegative F, O, N. The hydrogen atoms are left with a positive charge and are attracted to the electronegative atoms of other molecules.
London Dispersion Forces
The weak forces of attraction between all atoms and molecules caused by temporary dipoles
Metallic bonding
The bonding responsible for typical metallic properties such as malleability, ductility, and electrical conductivity in metals and alloys. Each atom loses its outer electron to form positive ions. Regular crystalline structure with the delocalised electrons attracted to the positive ions.
Miscibility
The ability for liquids to mix perfectly together.
Monatomic
A term used to describe the noble gases since they are composed of individual atoms which do not bond to each other. Held together by LDF in liquid and solid state.
Non-polar covalent bond
A covalent bond where both atoms share the electrons equally. This exists with all elements that exist as molecules (Cl2 and S8) since the atoms joining are identical. Also in compounds that have a small difference in electronegativity, such as hydrocarbons.
Permanent dipole to permanent dipole
The attraction between molecules which possess a permanent dipole because of the presence of polar bonds
Polar covalent bonds
Bonds formed between non-metallic atoms by sharing a pair of electrons. If the atoms have considerably different electronegativities the electrons are not shared equally. The more electronegative atom become delta negative in comparison with the other atom. As a result the bond is polar.
Temporary dipoles
Formed in all atoms where an excess of electrons is formed at one part of the atom. Temporary dipoles are the basis of LDP
Viscosity
How thick a liquid is
