1. Science 10

2. Covalent Compounds Covalent compounds are formed between non- metals only Nonmetals combine in more than one ratio therefore we must use prefixes to indicate the number of atoms in each element in the formula. Prefixes are placed in front of the element name

3. Here are the prefixes you'll need to remember PrefixNumber Mono1 Di2 Tri3 Tetra4 Penta5 Hexa6 Hepta7 Octa8 Nona9 Deca10

4. Naming Rules The first word is the name of the element that appears first in the formula. The prefix is placed before this name to indicate how many atoms of that element there are The second word consists of: The appropriate prefix designating the number of atoms of the second element The root of the name of the second element The suffix “ide”

5. Some Exceptions… When the first element would have the prefix mono we do not put it in the name Ex: CO 2 would be carbon dioxide NOT monocarbon dioxide When two a’s or o’s will appear next to each other we drop one Ex. CO would be carbon monoxide NOT carbon monooxide

6. Try Some Examples N 2 O N 2 O 5 SiO 2 PI 3

7. Name or Give the formula 1. CS 2 2. sulfur dioxide 3. diarsenic trioxide 4. P 4 O 10