CHAPTER 4 CONCURRENT ENROLLMENT

LEWIS STRUCTURE Elemental symbol represents the nucleus and core electrons Elemental symbol represents the nucleus and core electrons Octet rule Octet rule Atoms will gain or lose valence electrons to have an outer electron arrangement the same as a noble gas Atoms will gain or lose valence electrons to have an outer electron arrangement the same as a noble gas Usually consisting of eight electrons Usually consisting of eight electrons Ionic bonds Ionic bonds Attraction of opposite charged ions Attraction of opposite charged ions Covalent bonds Covalent bonds Attractive force between two atoms that are sharing some of their valence electrons Attractive force between two atoms that are sharing some of their valence electrons

IONIC COMPOUNDS Ions are atoms that have gained or lost electrons so now they have a charge. Ions are atoms that have gained or lost electrons so now they have a charge. Isoelectronic species Isoelectronic species An Atom and ions that all have the same electron configuration An Atom and ions that all have the same electron configuration Ionic compounds Ionic compounds The positive ion total charge has to cancel out the negative ion total charge to form a compound The positive ion total charge has to cancel out the negative ion total charge to form a compound

IONS Binary compounds have only single atom ions Binary compounds have only single atom ions Polyatomic ions Polyatomic ions Covalently bonded groups of atoms that have a charge Covalently bonded groups of atoms that have a charge Stable form of an ionic compound is a crystal Stable form of an ionic compound is a crystal Oppositely charge ions occupy a three-dimensional geometric shape that is called a CRYSTAL LATTICE Oppositely charge ions occupy a three-dimensional geometric shape that is called a CRYSTAL LATTICE Formula mass, CO 2 Formula mass, CO 2

VSEPR THEORY Mutual repulsion of electron pairs to predict molecular shapes Mutual repulsion of electron pairs to predict molecular shapes In geometry, multiple bonds behave as a single bond in repulsion In geometry, multiple bonds behave as a single bond in repulsion Lone pairs (electrons) take up more space than when bonded, this will change the bond angles Lone pairs (electrons) take up more space than when bonded, this will change the bond angles Hybrid sublevels Hybrid sublevels 3 atoms/ 2 bonded electron pairs sp 3 atoms/ 2 bonded electron pairs sp 4 atoms/ 3 bonded electron pairs sp 2 4 atoms/ 3 bonded electron pairs sp 2 5 atoms/ 4 bonded electron pairs sp 3 5 atoms/ 4 bonded electron pairs sp 3

POLARITY Electronegativity Electronegativity How much an atom wants electrons, attraction for shared electrons How much an atom wants electrons, attraction for shared electrons Bond polarization Bond polarization Shared electrons being attracted to the more electronegative atom Shared electrons being attracted to the more electronegative atom Covalent bonds Covalent bonds Polar Polar Electrons are being shared unequally Electrons are being shared unequally Nonpolar Nonpolar Electrons are being shared equally Electrons are being shared equally

CONTINUE Polar molecule Polar molecule Polarized bonds where the charge are distribute unevenly throughout the molecule Polarized bonds where the charge are distribute unevenly throughout the molecule Nonpolar molecule Nonpolar molecule No polarized bonds or polarized bonds where the charges are distributed evenly throughout the molecule No polarized bonds or polarized bonds where the charges are distributed evenly throughout the molecule

EXAMPLES Nonpolar compounds are named using Greek prefixes Nonpolar compounds are named using Greek prefixes All nonpolar compounds named will have no more than two elements in it All nonpolar compounds named will have no more than two elements in it The second element ends in –ide The second element ends in –ide mono- is never used with the first element mono- is never used with the first element

INTERPARTICLE FORCES Forces that keep particles together Forces that keep particles together Network solid Network solid a solid where lattice sites are occupied by atoms covalently bonded to each other a solid where lattice sites are occupied by atoms covalently bonded to each other metallic bond metallic bond attractive forces that holds metal atoms together attractive forces that holds metal atoms together metal atoms valence electrons move freely through empty or partly empty sublevels these are called CONDUITS metal atoms valence electrons move freely through empty or partly empty sublevels these are called CONDUITS

CONTINUED Dipolar forces Dipolar forces The positive end from one polar molecule will be attracted to the negative end of another The positive end from one polar molecule will be attracted to the negative end of another Hydrogen bonding Hydrogen bonding A molecule containing a very electronegative element (O, N, and F) and hydrogen. the electronegative atom of one molecule will be attracted to the hydrogen atom of another molecule A molecule containing a very electronegative element (O, N, and F) and hydrogen. the electronegative atom of one molecule will be attracted to the hydrogen atom of another molecule