chap 3 key terms Flashcards
(41 cards)
allotrope
o Allotrope- Different forms of the same element in which the atoms combine in different ways.
amorphous
o Amorphous- A structure that has no consistent arrangement of particles.
asymmetrical molecule
o Asymmetrical molecule- A molecule in which the polar bonds are unevenly (or asymmetrically) distributed. The bond dipoles do not cancel and an overall molecular dipole is created.
combustion
o Combustion- A rapid reaction with oxygen accompanied by the release of large amounts of heat: also called burning.
covalent bond
o Covalent bond- The force of attraction formed when one or more pairs of electrons are shared between two nuclei.
covalent lattice
o Covalent lattice- A 3D lattice structure formed from covalently bonded non-metal atoms.
covalent network lattice
o Covalent network lattice- An arrangement of atoms in a lattice in which there are strong covalent bonds between the atoms in all three dimensions.
covalent layer lattice
o Covalent layer lattice- an arrangement of atoms in a lattice in which there are strong covalent bonds that have formed in a layer.
diamond
o Diamond- A form of pure carbon that is the hardest naturally occurring substance.
diatomic molecule
o Diatomic molecule- A molecule formed from two atoms only, e.g. Cl2.
dipole
o Dipole- The separation of positive and negative charges in a molecule.
dipole-dipole attraction
o Dipole-dipole attraction- A form of intermolecular force that occurs between polar molecules where the partially positively charged end of one molecule is attracted to the partially negatively charged end of another molecule.
dispersion force
o Dispersion force- the force of attraction between molecules due to temporary dipoles induced in the molecules. The temporary dipoles are the result of random fluctuations in the electron density.
double covalent bond
o Double covalent bond- A covalent bond in which four electrons (two electron pairs) are shared.
electron density
o Electron density- The concentration of electrons that usually refer to the regions around an atom or molecule.
electron group
o Electron group- A region of negative charge around an atom, which could be either different types of covalent bonds or a non-bonding pair.
electronegativity
o Electronegativity- The ability of an atom to attract electrons in a covalent bond towards itself.
graphite
o Graphite- A form of carbon in which the carbon atom are arranged in layers.
hydrogen bond
o Hydrogen bond- A type of intermolecular, dipole-dipole force where a hydrogen atom is covalently bonded to a highly electronegative atom such as oxygen, nitrogen or fluorine. Due to the disparity of electronegativity values between the atoms involved, the hydrogen develops a partial positive charge and bonds to lone pairs of electrons on neighbouring atoms of oxygen, nitrogen or fluorine.
instantaneous dipole
o Instantaneous dipole- A net dipole formed in a molecule due to temporary fluctuations in the electron density in the molecule.
intermolecular force
o Intermolecular force- an electrostatic force of attraction between molecules, including dipole-dipole forces, hydrogen bonds and dispersion forces.
intramolecular force
o Intramolecular bond- a force that holds the atoms within a molecule together
Lewis structur
o Lewis structure- electron dot structure.
molecular formula
o Molecular formula- A formula of a compound that gives the actual number and type of atoms present in a molecule. It may be the same as or different from the empirical formula.