Chemical Bonding union between atoms Charge separation Transfer of electrons No charge separation Electrons shared between atoms Opposites attract δ+ δ– Polar Pure covalent covalent bond made made upofnonmetal nonmetal atoms atoms sharing sharing electrons with with nonmetal nonmetal atoms atoms Metallic Ionic bond bond - metal -bond metal cations ionsup and in aofnonmetal sea of (mobile) anions bonded electrons inelectrons a 3D array called a crystal lattice • ionic Unequal sharing oftogether electrons gives by riseelectrostatic to partial charges; positive δ++]and negative Equalbonds sharing electrons between two atoms; electrons shared equally metals conduct are of electricity held tightly ion chargens; [M attracts [X– ] δ– • the bond line (—) represents the sharing two, : , eletrons of two, :being , electrons shared; (H :X) (X:X) (H:H) +______> metals ionic substances conduct heat; are usually (hot as found well asascold) brittle solids. •Classic both the more atoms have the atom electronegativities has theand greatest and pullshare on electrons sharedinto (X:X) electrons (H:H) (H :X) equally unequally metals Example: areelectronegative ductile table (tosame draw salt, into NaCl wire) malleable (tothe hammer sheets) Classic Examples: stomach the sevenacid, diatomic H—Cl, molecules the waterHmolecule —H 2, N2, O2,HF—O 2, Cl 2 Br2, I2 Physical Bonding attractions between molecules Chemical bond (___) versus Physical attraction (||||||||||||||) δ+ δ– δ+ δ– Dispersion forces are the weakest attractive forces between all molecules hydrogen bonding - attractive strongest attractive force between IF the following is met: dipole ||||||||| dipole - an force between the poles ofmolecules, polar molecules ONLY intermolecular observed bybetween nonpolar molecules is the • molecule X = bond N O F dispersive forces athe solid linemust (—)have representsforce a chemical atoms gray circle a nonpolar spherical container ofO—H evenlymolecules dispersed • athe hydrogen must be”attached to X N—H F—H electrons hashed line “represents ||||||||| represents anasattractive force between polar +] show +]“attracts nonpolar molecules little between •X mustcharges; have an [δ available electron pair : ” : N—H :+]O—H : –F—H partial attracts [δ– or ]|||||||||no [δattraction [δ– ]||||||||| [δnonpolar attractsmolecules [δ ]||||||||| [δ+] Examples: theasseven diatomic molecules H2,||||||||||| NH—Cl O2, F||||||||||| , I2: X—H •Classic bonding is represent hash mark “||||||||||| ” |||||||||: H—Cl N—H : F—H Classic example: H—Cl ||||||||| H—Cl ||||||||| H—Cl ||||||||| 2:,O—H 2, Cl 2 Br2||||||||||| Classic examples: water H2O, ammonia NH3, hydrofluoric acid HF 1