chem 8

covalent bond

a chemical bond that results from the sharing of valence electrons

endothermic reaction

a chemical reaction or process in which a greater amount of energy is required to break the existing bonds in the reactants then is released when the new bonds form in the product molecules

exothermic reaction

a chemical reaction or process in which more energy is released when the bonds break than the energy required to break them

Lewis structure

a model that uses electron dot structures to show how electrons are arranged in molecules

molecule

form when two or more atoms covalently bond and is lower in potential energy the its constituit atoms

pi bond

a bond that is formed when parallel orbitals overlap

sigma bond

single covalent bond that is formed when an electron pair is shared by the direct overlap by bonding orbitals

oxyacid

any acid that contains hydrogen and an oxyianion

coordinate covalent bond

forms when one atom donates a pair of electrons to be shared with an atom or ion that needs two electrons to become stable

resonance

condition that occurs when more than one valid Lewis structure exists for the same molecule

structural formula

a molecular model that uses symbols and bonds to show relative positions of atoms; can be predicted for many molecules by drawing the Lewis structure

hybridization

a process in which atomic orbitals are mixed to form new, identical hybrid orbitals

VSEPR model

based on an arrangement that minimizes the repulsion of shared and unshared pairs of electrons around the central atom

polar covalent bond

a type of bond that forms when electrons are not shared equally