Chemical Formula Review
Chemical Formulas Review: Nomenclature and Formula Writing
Naming Simple Compounds
There are four naming systems you should familiarize yourself with to succeed on the SAT II Chemistry exam. The trick is recognizing which naming system to use. Here are the guidelines: * If the compound starts with H, it is an acid. Use the naming acids rules. * If the compound starts with C and contains quite a few H’s and perhaps some O’s, it is organic. Use the naming organic compounds rules. * If the compound starts with a metal, it is most likely ionic. Use the naming binary ionic compounds rules. * If the compound starts with a nonmetal other than H or C, use the naming binary molecular compounds rules.
It is also essential that you memorize some common polyatomic ions. Polyatomic ions behave as a unit. If you need more than one of them, enclose them in parentheses when you write formulas. You need to know their names, formulas, and charges. If you learn the nine that follow, you can get many others from applying two simple patterns. Name of polyatomic ion | Formula and charge | Ammonium ion | NH4+ | Acetate ion | C2H3O2- | Cyanide ion | CN- | Hydroxide ion | OH- | Nitrate ion | NO3- | Chlorate ion | ClO3- | Sulfate ion | SO42- | Carbonate ion | CO32- | Phosphate ion | PO43- | * Pattern 1: The -ates “ate” one more oxygen than the -ites and their charge doesn’t change as a result! For instance, if you know nitrate is NO3-,then nitrite is NO2-.If you know phosphate is PO43-,then you know phosphite is PO33-.You can also use the prefixes hypo- and per- with the chlorate series. Perchlorate, ClO4-,was really “hyper and ate yet another oxygen” when compared to chlorate, ClO3-.Hypochlorite is a double whammy: it is -ite and therefore “ate” one less oxygen than chlorate and it is hypo-, which means “below,” so it “ate” even one less oxygen than plain chlorite, so its formula is ClO-. You can also substitute the other halogens for Cl and
Naming Simple Compounds
There are four naming systems you should familiarize yourself with to succeed on the SAT II Chemistry exam. The trick is recognizing which naming system to use. Here are the guidelines: * If the compound starts with H, it is an acid. Use the naming acids rules. * If the compound starts with C and contains quite a few H’s and perhaps some O’s, it is organic. Use the naming organic compounds rules. * If the compound starts with a metal, it is most likely ionic. Use the naming binary ionic compounds rules. * If the compound starts with a nonmetal other than H or C, use the naming binary molecular compounds rules.
It is also essential that you memorize some common polyatomic ions. Polyatomic ions behave as a unit. If you need more than one of them, enclose them in parentheses when you write formulas. You need to know their names, formulas, and charges. If you learn the nine that follow, you can get many others from applying two simple patterns. Name of polyatomic ion | Formula and charge | Ammonium ion | NH4+ | Acetate ion | C2H3O2- | Cyanide ion | CN- | Hydroxide ion | OH- | Nitrate ion | NO3- | Chlorate ion | ClO3- | Sulfate ion | SO42- | Carbonate ion | CO32- | Phosphate ion | PO43- | * Pattern 1: The -ates “ate” one more oxygen than the -ites and their charge doesn’t change as a result! For instance, if you know nitrate is NO3-,then nitrite is NO2-.If you know phosphate is PO43-,then you know phosphite is PO33-.You can also use the prefixes hypo- and per- with the chlorate series. Perchlorate, ClO4-,was really “hyper and ate yet another oxygen” when compared to chlorate, ClO3-.Hypochlorite is a double whammy: it is -ite and therefore “ate” one less oxygen than chlorate and it is hypo-, which means “below,” so it “ate” even one less oxygen than plain chlorite, so its formula is ClO-. You can also substitute the other halogens for Cl and