HONORS CHEMISTRYUnit C: Chemical Bonding, Formulas, Reactions & Equations

CHAPTER SEVEN: CHEMICAL FORMULAS & COMPOUNDS

NAMES & FORMULASuCHEMICAL FORMULAS indicate the

the elements present and the number of atoms of each element

uUses SYMBOLS and SUBSCRIPTSuSometimes uses PARENTHESES for

polyatomic ions

IONIC COMPOUND FORMULASuIONIC COMPOUNDS are

represented by FORMULA UNITS uReduced ratio of cation : anionuCATION 1st, ANION 2nd

uCHARGE COUNTS! (Must sum to zero)

ION CHARGESuIon charge is related to number valence

electronsuGroup 1: 1+ , Group 2: 2+ , Aluminum: 3+

uGroup 15: 3- , Group 16: 2- , Group 17: 1-

uTransition Metals are usually 2+, but can range from 1+ to 4+

uSPECIALS: Pb (lead) & Sn (tin) can be either 2+ or 4+

ION CHARGES

FORMULAS UNITSuCheck Charge! Sum to zero!uIf the charges are equal and

opposite then the ratio is 1:1uWhen charges are not equal

and opposite, SWAP & DROP!uUse parentheses for polyatomic

ions when multiple are included

NAMING IONIC COMPOUNDSuIonic compounds list the

cation first, anion seconduCation name is unchangeduAnion name is changed to

–ide ending by dropping the last syllable or two

uPolyatomic ions keep their name

ROMAN NUMERALSuROMAN NUMERALS are used

to indicate charge on transition metals, Pb, Sn

u I = 1uII = 2uIII = 3uIV = 4

MOLECULAR COMPOUNDSuMOLECULAR FORMULAS show

the the elements and actual number of atoms in a molecule

uThe formulas list the least electronegative element(s) first

uH2O, CO2, NO, PCl3

MOLECULAR COMPOUNDSuBINARY MOLECULAR

COMPOUND NAMES are simple and involve 2 elements

uGREEK PREFIXES are used to “describe” the number of atoms

uOnly the second element has an –ide ending change

MOLECULAR COMPOUNDS

ACIDSuACIDS are molecular

compoundsuCommon ACIDS have specific

namesuBINARY ACIDS contain

Hydrogen and and AnionuOXYACIDS contain Hydrogen,

Oxygen, and an additional (3rd) element

6 COMMON ACIDSuHCl – Hydrochloric AciduHNO3 – Nitric AciduH2SO4 – Sulfuric AciduH3PO4 – Phosphoric AciduCH3COOH (C2H4O2) – Acetic AciduH2CO3 – Carbonic Acid