THE MORE COMMON ELEMENTS AND COMPOUNDS 19 



The ending -ic means common, as in ferric chlorid (FeCl 3 ), and sulfuric 

 acid (H 2 SO 4 ). 



The ending -ous means less, as less chlorin, in ferrous chlorid (FeCk), and 

 less oxygen, in sulfurous acid (H 2 SO 3 ). 



The ending -ate means common,- usually suggests oxygen, as in sodium 

 nitrate (NaNO 3 ). 



The ending -ite means less, as in sodium nitrite (NaNO 2 ). 



The prefix hypo- means still less, as in hyposulfurous acid (H 2 SO 2 ), or in 

 sodium hyposulfite (Na 2 SO 2 ). 



The prefix per- means more, as in persulfuric acid (H 2 S 2 O 8 ). 



The prefix hydro- means hydrogen and no oxygen, as in hydrochloric acid 

 (HC1). 



The ending -ic in the names of acids without the prefix hydro- suggests 

 oxygen, as in sulfuric acid (H 2 SO 4 ). 



The ending -id is used for binary compounds. 



Hydro-ic acids yield -id salts; other -ic acids yield -ate salts; and -ous 

 acids yield -ite salts. 



Hydroxid oxids. We have, not only oxids and hydroxids, but 

 also compounds that are part oxid and part hydroxid, as shown 

 by the structure formulas given in the first column in the following 

 classified list: 



C1OH . . . Hypochlorous acid, HC1O. 



OC1OH . . Chlorous acid, HC1O 2 . 



O 2 C1OH . . Chloric acid, HC1O 3 . 



O 3 C1OH . . Perchloric acid, HC1O 4 . 



S(OH) 2 . . Hyposulfurous acid, H 2 SO 2 . 



OS (OH) 2 . . Sulfurous acid, H 2 SO 3 . 



O 2 S(OH) 2 . Sulfuric acid, H 2 SO 4 . 



ONOH . . Nitrous acid, HNO a . 



O 2 NOH . . Nitric acid, HNO 3 . 



Here we have an atom of chlorin, sulfur, or nitrogen, one or 

 more oxygen atoms, and also one or more hydroxyl groups, in the 

 same molecule, and the increasing valence of certain elements is 

 illustrated, that of chlorin from i (in HC1) to 3, 5, and 7, in 

 the compounds shown; that of sulfur from 2 (in H 2 S and CS 2 ) 

 to 4 and 6, in the compounds here shown; and nitrogen with three 

 and with five bonds. 



The formulas, showing both oxid and hydroxid characters, can 



