Question | Answer |
exothermic | more energy is given out than needs to be put in it will be released as heat |
endothermic | extra heat is needed to be added because more energy is required to break the reactant bonds than is given out when the products are formed |
intramolecular forces | bonds that are present between atoms within a molecule |
electron affinity | energy change when an electron is added to the neutral specie to form a negative ion |
lattice enthalpy | measure of the strength of bonds in that ionic compound |
polyatomic ions | positive or negative ions that are formed when more than one element is joined to another |
single covalent bond | one pair of electrons is shared between two atoms |
Lewis Structure | diagram that show all the pairs of outer electrons in a molecule |
lone pair | non-bonded pair |
double covalent bond | each atom shares two electrons with the other |
triple covalent bond | three shared pairs of electrons between the two atoms |
coordinate (or dative) covalent bond | both electrons from a shared pair originate from the same atom, formed when a non-bonding pair of electrons on one of the atoms donates its electrons to an atom or ion that is deficient in electrons |
delocalized | when ion contains an extra proton with the positive charge spread out over the whole ion |
resonance hybrids | three possible extreme structures |
dipole moment | molecule placed between 2 electrically charged plates -end will be attracted to the positive plate and +end will be attracted to negative plate |
valence shell electron pair repulsion | because of the repulsion between pairs of electrons around the central atom in the molecule or ion, the pairs of electrons are arranged so they are as far away from each other as possible |
stereochemistry | way in which atoms are orientated in space |
van der Waal's forces | attractive or repulsive force between molecules other than those due to covalent bonds or to the electrostatic interaction of ions with each other or neutral molecules |
dipole | pair of equal and opposite electric charges or magnetic poles separated by a small distance |
hydrogen bonding | attractive interaction of a hydrogen atom with electronegative atom |
allotropy | can exist in more than one physical form or allotrope |
fullerenes | molecules composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube |
nanotubes | long tubes that can be closed or open at one end, extremely small diameter |
delocalized | atoms of metals bond together in solid state one or more valence electrons becomes detached from each atom electrons are free to move in the metallic structure |
malleable | metal can be beaten into shape without breaking |
ductile | metal can be drawn into a wire |
phlogiston | hypothetical substance once believed to be present in all combustible materials to be released during burning |
molecular orbital theory | based on quantum mechanics and looks at the combination of atomic orbitals to form molecular orbitals and hybrid orbitals |
bonding molecular orbital | molecular orbital with a lower energy that electrons tend to fill first because of lower energy |
anti-bonding orbital | molecular orbital with higher energy than either of 2 atomic orbitals that combined destructively to decrease the electron density |
sigma molecular orbital | 2 s orbitals combine and resulting bonding molecular orbital has a single shape with no plane of zero electron density through it |
sigma bond | 2 s orbitals, s and p, or 2 p orbitals bonded between atoms |
pi molecular orbital | direct sharing of electron between a atoms' p orbitals |
pi bond | covalent chemical bonds when 2 lobes of one involved electron orbital overlap 2 lobes of the other involved electron orbital |
paramagnetism | relating to or being a substance in which an induced magnetic field is parallel and proportional to the intensity of the magnetizing field |
bond order | number of chemical bonds between a pair of atoms |
hybridization | act of mixing different species or varieties of animals or plants and thus to produce hybrids |
electrophiles | reactants that are attracted to electrons |
delocalization enthalpy/resonance energy | 150 KJ/mol characteristic energy at which the amplitude of a resonance phenomenon |