Naming Covalent Compounds

Science 10

Covalent CompoundsCovalent 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

Here are the prefixes you'll need to remember

Prefix Number

Mono 1

Di 2

Tri 3

Tetra 4

Penta 5

Hexa 6

Hepta 7

Octa 8

Nona 9

Deca 10

Naming RulesThe 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 elementThe root of the name of the second elementThe suffix “ide”

Some Exceptions…When the first element would have the prefix

mono we do not put it in the nameEx: CO2 would be carbon dioxide

NOT monocarbon dioxide

When two a’s or o’s will appear next to each other we drop oneEx. CO would be carbon monoxide

NOT carbon monooxide

Try Some ExamplesN2O

N2O5

SiO2

PI3

Name or Give the formula1. CS2

2. sulfur dioxide

3. diarsenic trioxide

4. P4O10