ch 3 – Chemistry – Flashcards
Unlock all answers in this set
Unlock answers| octet rule |
| atoms of representative elements form bonds to gain access to 8 outer e- |
| valence electrons |
outer e-
1) completely gain or lose e- +cations -electrons
2)share e- |
| ionic compounds- metals |
lose 1-3e- go back to Noble Gas conf. Takes on charge cations |
| ionic compounds- nonmetals |
gain 1-3 e- go to next Noble Gas conf. takes on charge anions -, -2, -3 |
| formula units |
| lowest whole number ratio of elements |
| ions |
| attracted to each other by electrostatic forces |
| covalent bonds between nonmetals |
| share electrons |
| lewis structures |
show how atoms are joined
show unshared e- show charge, if any |
| resonance |
attempt to describe true nature of bonding-usually with multiple bonds
rules: correct #e- obey rules of bonding atoms NOT moved |
| electronegativity |
ability of an atom in a bond to attract e- toward it
increase left-right increase top-bottom |
geometry of molecules (figuring out) |
1. draw lewis structure 2. count total # "things" attached to central atom |
| valence-shell electron-pair repulsion model |
| VSEPR |
| the chemical bond's GOAL |
| to fill outer S;P orbitals |
| formal charge |
| (V-F) |
| Polarity of molecules |
1) polarity of bonds =polarity of molecules 2) Geometry of molecules; |
nonpolar ; |
| symmetrical molecular structure |
| polar |
| nonsymmetrical molecular structure |
| polyatomic ions |
-a group of covalently bound atoms which have no charge -complex ions -nonmetals |
| nomenclature |
-need to recognize type of compound ionic and "mixed"; (with polyatomic ions) |
nomenclature types metal |
ionic one charge Group 1,2,3 ; name metal then metal with -ide ending |
nomenclature types nonmetal |
ionic, covalent binary (2 elements) ; w/ polyatomic ions |
| binary metal |
| one charge |
| stock method |
metal name (roman numeral) nonmetal-ide ; lower charge=ous higher charge= ic |
| metal + polyatomic ion (ionic) |
NaCN = Na+CN- = sodium cyanide |
nonmetal+nonmetal (molecules) share electrons |
write and name "most metal-like" 1st (least electronegative) ; name 1st nonmetal 1st if;1 give prefix ; 2nd one 2nd (-ide) give prefix ; di tri tetra penta hexa hepa octa nona deca |
| chemical reactions |
(reactants) ; ;(products) A+B yields C+D ; ; balance!!! need to have the same number of each element on either side of equation |
| rules of balancing chemical equations |
1. subscripts of compounds are fixed. do not change them when balancing equation 2. coefficients miust be in smalles whole number ration 3. coefficients multiply all numbers in formula |
| helpful hints for balancing equations |
1. do atoms other than H;O first - compound with most atoms first -if polyatomic ion is unchanged, treat as one unit 2. do rest of atoms except H;O 3. do H;O- choose the one in fewest compounds first 4. check balance- if any fractions were used, multiply through to get whole numbers |
